Research Highlights
Here we show recent research results from the Radio Astronomy/Very-Long-Baseline Interferometry department.
Understanding AGN jets with the TELAMON programme
28 March 2024
A paper published today shows the results obtained by a team led by Florian Eppel, including scientists from the MPIfR and the University of Würzburg, reporting on the first results from the TELAMON program (PI. M. Kadler). The TELAMON programme uses the 100 m Effelsberg telescope to monitor radio spectra of active galactic nuclei (AGN), in particular TeV blazars and neutrino-associated AGN. This study focuses on the characterisation of a main sample of TeV-detected blazars. Data from about 2.5 years of observations were analysed, covering frequencies from 14 GHz to 45 GHz. In the pilot phase, 59 TeV-detected blazars in the northern hemisphere were observed. Basic data reduction and calibration procedures were applied to the TELAMON data, and an averaging method was used to compute mean light curves for the sources. The results show that TeV-selected blazars in the sample typically have a flat radio spectrum, with a median spectral index of -0.11. These results are consistent with previous studies of TeV-selected blazars. Compared to the GeV-selected sample, the TELAMON sources have a lower radio flux density, which is consistent with the spectral characteristics of TeV-emitting blazars. The spectral index distribution of the TeV-selected blazar sample is similar to that of the GeV-selected samples. In addition, a strategy for tracking the light curve evolution is presented for future variability and correlation analysis. More details can be found in the publication, appeared today in Astronomy & Astrophysics, here.
Selected media echo and parallel press releases (Sgr A* 2017 EHT polarisation image release)
Parallel Press Releases:
- Event Horizon Telescope: Astronomers Unveil Strong Magnetic Fields Spiraling at the Edge of Milky Way’s Central Black Hole
- Harvard-Smithsonian Center for Astrophysics: Astronomers Unveil Strong Magnetic Fields Spiraling at the Edge of Milky Way’s Central Black Hole
- European Southern Observatory: Astronomers unveil strong magnetic fields spiraling at the edge of Milky Way’s central black hole
- National Radio Astronomy Observatory: Astronomers Unveil Strong Magnetic Fields Spiraling at the Edge of Milky Way’s Central Black Hole
English:
- Sky & Telescope, 27 March 2024, Strong Magnetic Fields Swirl Near Milky Way
- Space.com (Robert Lea), 27 March 2024, New view of the supermassive black hole at the heart of the Milky Way hints at an exciting hidden feature (image)
- Phys.org (Amy C. Oliver), 27mar2024, Astronomers unveil strong magnetic fields spiraling at the edge of Milky Way's central black hole
- Forbes (Jamie Carter), 27mar2024, See The Jaw-Dropping New Image Of The Black Hole At The Heart Of The Milky Way
- Astronomy.com (Mark Zastrow), 27mar2024, The Milky Way’s central black hole could have a hidden jet
- Science News (Adam Mann), 27mar2024, A new image reveals magnetic fields around our galaxy’s central black hole
- New Scientist (Alex Wilkins), 27mar2024, New view of our galaxy's black hole reveals a swirling magnetic field (including YouTube video)
- The Independent (Andrew Gribbin), 27mar2024, Scientists reveal astonishing image of black hole in our galaxy
- EarthSky (Kelly Kizer Whitt), BREAKING! Milky Way’s black hole in new image
- BBC Science Focus (Tom Howarth), 27mar2024, Stunning new image of black hole at centre of our galaxy revealed
- The Irish News (Nina Massey), 27mar 2024, New image shows magnetic fields at edge of Milky Way’s central black hole
- Guardian Series, 27mar2024, New image shows magnetic fields at edge of Milky Way’s central black hole
- Science Alert (Michele Starr), 27mar2024, Magnetic Fingerprints of The Milky Way's Black Hole Revealed in Stunning Image
- idw Online, 27mar2024, Astronomers Unveil Strong Magnetic Fields Spiraling at the Edge of Milky Way’s Central Black Hole
- Universe Today (Alan Boyle), 27mar2024, New View Reveals Magnetic Fields Around Our Galaxy’s Giant Black Hole
- Science News (Adam Mann), 27mar2024, A new image reveals magnetic fields around our galaxy’s central black hole
- Business Insider (Morgan McFall-Johnsen), 27mar2024, This new photo of a supermassive black hole is unlike any before, showing powerful magnetic fields spiraling around it
- Science Alert (Michelle Starr), 28mar2024, Magnetic Fingerprints of The Milky Way's Black Hole Revealed in Stunning Image
Spanish:
- Agencia SINC, 27mar2024, Primera imagen en luz polarizada del agujero negro de nuestra galaxia
- El Mundo, 27mar2024, Una nueva imagen del agujero negro de la Vía Láctea desvela potentes campos magnéticos
- Granada Hoy, 27mar2024, El Instituto de Astrofísica de Andalucía de Granada participa de la primera imagen en luz polarizada del agujero negro
- Ciencia Plus, 27mar2024, Fuertes campos magnéticos rodean el agujero negro central de la galaxia
- InfoBAE, 27mar2024, Una nueva imagen del agujero negro de la Vía Láctea desvela potentes campos magnéticos
- Gizmodo, 27mar2024, Nueva imagen expone el intenso campo magnético del agujero negro supermasivo de la Vía Láctea
- Agencia Efe, 27mar2024, Una nueva imagen del agujero negro de la Vía Láctea desvela potentes campos magnéticos
- Europa Press, 27mar2024, Fuertes campos magnéticos rodean el agujero negro central de la galaxia
- La Brújula Verde (Guillermo Carvajal), 27mar2024, Astrónomos descubren fuertes campos magnéticos en espiral en el borde del agujero negro central de la Vía Láctea
- Wired.com (Jorge Garay), 27mar2024, Nueva foto del agujero negro en el centro de la Vía Láctea revela sus poderosos campos magnéticos
- Deutsche Welle, 28mar2024, Imagen desvela campos magnéticos en espiral en Vía Láctea
- La Voz de Galicia, 28mar2024, El agujero negro de nuestra galaxia genera potentes campos magnéticos
- Radio France International, 28mar2024, Espiral de fuertes campos magnéticos rodea el agujero negro de la Vía Láctea
- Meteored (Zeus Valtierra), 28mar2024, Los misterios magnéticos de Sagitario A*: girando en la espiral del cosmos
- National Geographic en Español, 28mar2024, Sagitario A*: Revelan nuevas imágenes del agujero negro en el corazón de nuestra galaxia
- El Periódico (Pablo Javier Piacente), 29mar2024, Detectan campos magnéticos desconocidos en el agujero negro supermasivo de la Vía Láctea
German press echo here (VLBI Department Highlights German version)
Selected media echo and parallel press releases (Perseus A 2017 EHT image release)
English:
- Robert Lea, Space.com, 03 February 2024 quoting Georgios F. Paraschos, Maciek Wielgus, and J. Anton Zensus: Event Horizon Telescope spies jets erupting from nearby supermassive black hole
Selected media echo and parallel press releases (M87 2018 EHT image release)
Here selected parallel press releases and news & views on the A&A publication of the Messier 87* images by the Event Horizon Telescope from observations in 2018.
English:
- Alex Wilkins, New Scientist, 18 January 2024, quoting Eduardo Ros: New fiery doughnut is our most detailed glimpse of a black hole
- Daniel Clery, Science, 18 January 2024: Nearby galaxy’s giant black hole is real, ‘shadow’ image confirms
- Andrew Griffin, The Independent, 18 January 2024: First ever black hole to be pictured shown in new image
- William Hunter, Daily Mirror, 18 January 2024: Venture inside a 'monster' supermassive black hole: Incredible new image of M87 confirms the enormous void is 'active and feeding
- Adam Mann, Science News, 18 January 2024: Astronomers have snapped a new photo of the black hole in galaxy M87
- Jeremy Gray, PetaPixel, 18 January 2024: This is the Sharpest Black Hole Image Yet
- Ayanna Amadi, Medriva, 18 January 2024: Unveiling the M87 Black Hole: A Higher Resolution Image Reveals More
- Alfredo Carpineti, IFL Science, 18 January 2024: Brand New Image Of First Black Hole To Be Photographed Reveals Moving Shadow
- Camille M. Carlisle, Sky & Telescope, 18 January 2024: The black hole shadow in M87*: one year later
- Nina Massey, The Irish News, 18 January 2024: New image of supermassive M87 galaxy black hole released
- Robert Lea, Space.com, 19 January 2024: 2nd image of 1st black hole ever pictured confirms Einstein's general relativity (photo)
- The Paradise, 06 February 2024: New images from EHT offers evidence of a persistent black hole shadow
- The Spark Chronicles, 06 February 2024: We spent six years processing black hole images to come to one conclusion: Einstein was right
- Amit Malewasr, Tech Explorist, 06 February 2024: New images from EHT offers evidence of a persistent black hole shadow
- Paul Sutter, Astronomy, 06 February 2024: The 2nd photo of the M87 black hole is stunning, and more than a pretty picture
- Tejasri Gururaj, The Hindu, 09 February 2024: Earth-wide telescope confirms black hole shadow is ‘real’
- Morgan Hollis, Nature Astronomy, 15 February 2024: The persistent ring of M87* confirms predictions
- NRAO Press Release, 18 January 2024: New Details of Supermassive Black Hole’s Shadow Revealed
- UNAM Press Release, 18 January 2024: M87* One Year Later: Proof of a persistent black hole shadow
- Aalto Univ. Press Release, 18 January 2024: Scientists reveal new images of a black hole - Proof of a persistent black hole shadow
- IAA-CSIC Press Release, 18 January 2024: M87* One Year Later: Proof of a persistent black hole shadow
- ASIAA Press Release, 18 January 2024: New Images of M87*: Proof of a Persistent Black Hole Shadow
- Joint ALMA Observatory Press Release, 18 January 2024: M87* One Year Later: Proof of a persistent black hole shadow
- Univ. Würzburg Press Release, 19 January 2024: Scientists Reveal a Black Hole Shadow
- Chalmers Univ. Press Release, 18 January 2024: The famous black hole in M 87, one year later
German:
- Sibylle Anderl, Die Zeit, 18 January 2024: Dieser Donut ist wirklich ein Schwarzes Loch
- Justus Maximilian Univ. Würzburg Press Release, 19 January 2024: Neuer Blick zum Schwarzen Loch
- Goethe Univ. Frankfurt Press Release, 18 January 2024: Zweites Bild des Schwarzen Lochs M87*: Alle theoretischen Voraussagen bestätigt
Spanish:
- SINC, 18 January 2024: Nuevas imágenes del agujero negro M87* muestran las variaciones en su anillo
- Dennis Overbye, Infobae & New York Times, 30 January 2024: Nuevas imágenes de un agujero negro confirman la teoría de Einstein
- UNAM Press Release, 18 January 2024: La sombra del agujero negro persiste por al menos un año
Unraveling Blazar Mysteries: TANAMI's First-epoch S Band Images
16 January 2024
A team of astronomers led by the MPIfR PhD candidate Petra Benke presents a new publication on southern radio sources. The study focuses on the multi-wavelength emission from blazars, which are celestial objects that emit radiation across the electromagnetic spectrum, from radio to high-energy gamma rays. Recent successes in the study of blazar activity have come from quasi-simultaneous multi-wavelength monitoring programs made possible by the launch of the Fermi Gamma-ray Space Telescope in 2008. The team used VLBI to carry out sensitive, long-term monitoring of a comprehensive sample of gamma-energetic AGN. These observations were made with the Long Baseline Array (LBA) and other radio telescopes in the Southern Hemisphere at 13 cm wavelength (S-band) as part of the TANAMI program. The study presents the first light TANAMI S-band images, highlighting the TeV-detected sub-sample of the full TANAMI sample. The analysis examines the redshift, 0.1-100 GeV photon flux, and S-band core brightness temperature distributions of the TeV-detected objects. In particular, flat-spectrum radio quasars and low-synchrotron-peak sources have on average higher brightness temperatures than high-synchrotron-peak BL Lacs. In addition, sources with bright GeV gamma-ray emission show higher brightness temperatures compared to gamma-low sources. More details of the study can be found in the original paper here (preprint here).
Unveiling the Dynamic Landscape of BL Lacertae's Jet: First GMVA Observations with Upgraded NOEMA Facility
12 December 2023
In a study published today in the journal Astronomy & Astrophysics, a team of MPIfR astronomers led by Daewon Kim presents a comprehensive analysis of a single epoch Global mm-VLBI Array (GMVA) observation of the blazar BL Lacertae (BL Lac) at 3.5 mm wavelength in April 2021. In particular, the upgraded Northern Extended Millimetre Array (NOEMA) significantly increases the sensitivity of the GMVA, allowing it to image BL Lac during an unusually robust γ-ray flare. To gain meaningful insights into the inner subsecond jet of BL Lac and to assess the impact of NOEMA's contribution, the team used advanced data reduction techniques (including the pipeline rPICARD developed by MPIfR-affiliated scientist Michael Janssen) which yielded high-fidelity VLBI images. These results indicate a 2.5-fold improvement in image sensitivity with the inclusion of NOEMA. The jet exhibits a pronounced wiggling structure within the central parsec-scale of the core with a helical jet structure showing a sinusoidal pattern. Model fitting to the inner jet region reveals up to six features, the two innermost of which are very bright and compact, suggesting significant relativistic beaming. In addition, these observations reveal four prominent polarised nodes in the jet, two of which are located in the core region. This intriguing discovery prompts consideration of different physical scenarios to interpret the observations. This study represents a significant advance in the understanding of the dynamic nature of the BL Lacertae jet and opens avenues for further exploration and theoretical modelling. For more information, see the original publication here.
Selected Media Echo (RadioAstron Observations of 3C 279)
Some highlighted articles, for a complete picture, see the MPIfR web area here.
- Nature Astronomy News & Views - Michael Janssen (MPIfR & Radboud Univ.) - Filaments explaining blazar jet radio variability
- EuropaPress - Un telescopio virtual de 100.000 kilómetros se adentra en un blazar
- Phys.org - Astronomers capture formation of a powerful cosmic jet
- Csillagászat - Sandor Frey - Szétszálazott plazmanyalábot derített fel a Földnél is nagyobb virtuális rádióteleszkóp
- Space.com - Robert Lea - Supermassive black hole seen spinning ropes of plasma like a cosmic spider
Helical structures in the cosmic fountain emanating from Messier 87
09 October 2023
A team of researchers led by the MPIfR PhD candidate Alexei Nikonov has revealed intricate details of the cosmic jet within galaxy M87. Utilizing advanced technology, the team conducted high-resolution radio observations at 8 and 15 GHz over three consecutive days in May 2009, employing the VLBA, VLA, and Effelsberg 100 m telescope. The resulting images, boasting dynamic ranges exceeding 20,000:1, disclosed a limb-brightened jet and a subtle counter-jet with a steep spectrum. Analysis of the jet-to-counter-jet ratio facilitated the estimation of key physical parameters. Notably, the internal structure of the jet revealed three helical threads, indicative of Kelvin-Helmholtz instability in a supersonic flow with a Mach number of approximately 20 and an enthalpy ratio of around 0.3. A spectral index image generated at 8-15 GHz demonstrated spectrum flattening at the intersections of these helical threads, reinforcing the Kelvin-Helmholtz origin of the observed internal structure. Additional findings include the detection of polarized emission in the jet, Faraday rotation with a transverse gradient, and the presence of a helical magnetic field. Our study provides a comprehensive exploration of M87's cosmic jet, shedding light on its complex dynamics and contributing valuable insights to the field of astrophysics. More details can be found in the original publication at the Monthly Notices of the Royal Astronomical Society here.
Monitoring of radio galaxy M87 confirms black hole rotation
26 September 2023
The nearby radio galaxy M87, located 55 million light-years from the Earth and harboring a black hole 6.5 billion times more massive than the Sun, exhibits an oscillating jet that swings up and down with an amplitude of about 10 degrees, confirming the black hole's spin.
The study, which was headed by Chinese researcher Dr. Cui Yuzhu and published in Nature on Sept. 27, was conducted by an international team using a global network of radio telescopes, including RuSen Lu and Jae-Young Kim, affiliated to the MPI für Radioastronomie.
Through extensive analysis of telescope data from 2000–2022, the research team revealed a recurring 11-year cycle in the precessional motion of the jet base, as predicted by Einstein's General Theory of Relativity. The study links the dynamics of the jet with the central supermassive black hole, offering evidence that M87's black hole spins. More information can be found at the Nature paper cited above.
From hero to zero: the binary hypothesis for the quasar PSO J1134.2028+1.4075
24 August 2023
A study led by MPIfR PhD student Petra Benke, published today in the journal Astronomy & Astrophysics, takes a closer look at the enigmatic quasar PSO J334.2028+1.4075 (PSO J334). Initially thought to be a supermassive black hole (SMBH) binary system, the quasar's optical light curve showed periodic flux density variations. However, subsequent observations with the European Very Long Baseline Interferometry Network (EVN) and the Karl G. Jansky Very Large Array (VLA) provide a clearer picture: the source has a single parsec-scale radio feature, a kiloparsec-scale lobe-dominated quasar, and a possible precessing jet. Contrary to previous binary hypotheses, the evidence suggests that PSO J334 is a jetted active galactic nucleus with a single SMBH, rejecting the idea of a binary system in its central engine. The study highlights the importance of detailed radio analysis in understanding the complex structures of distant quasars. More details can be found in the original publication here.
A further success of the space-VLBI RadioAstron mission: discovery of a mini-cocoon around the restarted parsec-scale jet in 3C 84
17 August 2023
In the current issue publication in The Astrophysical Journal, an international team researchers led by Tuomas K. Savolainen from Aalto University, also affiliated to the MPIfR, unveiled a remarkable finding in the galaxy 3C 84. Utilizing space-VLBI observations, they detected a mini-cocoon surrounding a reactivated parsec-scale jet. These observations, conducted with a global array of radio telescopes, provided unprecedented resolution, revealing intricate sub-structures within the jet. Most notably, the 5 GHz image revealed low-intensity emissions from the cocoon-like structure, suggesting that the jet's increased power inflates a hot plasma bubble as it traverses the galaxy's central region. The study estimates the mini-cocoon's energy, pressure, volume, and its impact on the interstellar medium. The findings indicate that a significant portion of the jet's energy is transferred to this mini-cocoon, and its quasi-spherical shape influences the energy distribution in the surrounding medium, shedding new light on the dynamics of radio galaxies. This discovery has the potential to reshape our understanding of cosmic processes and will undoubtedly stimulate further exploration and discussion in the field of astrophysics. More information, at the original publication here.
Space-VLBI to probe the compactness of the central region of M87 at 13 mm wavelength
14 July 2023
RadioAstron has observed the central region of the well-known elliptical galaxy M 87, by using state-of-the-art 22 GHz space-VLBI in the framework of the RadioAstron mission. As part of the Nearby AGN Key Science Program, the galaxy was observed in February 2014. These observations, involving 21 ground stations and extending to Earth-sized projections, resulted in spatial resolutions as fine as 20 Schwarzschild radii, equivalent to a mere 150 microarcseconds. This probed details of the core region previously concealed. The most remarkable revelation is the identification of an extraordinarily high brightness temperature, surpassing 1012 K. This unexpected finding challenges existing theoretical frameworks and prompts astronomers to explore unconventional explanations, such as extreme Doppler boosting, unique jet perspectives, or novel particle acceleration mechanisms. This work, led by Jae-Young Kim from Kyungpook National University and also affiliated to the MPIfR are presented in the current issue of The Astrophysical Journal. More information can be found in the original publication here.
MOEA/D: A Novel Approach to Radio Astronomy Imaging
30 June 2023
In the vast realm of radio astronomy, image reconstruction remains an intricate puzzle. Despite the rising sensitivity and capabilities of telescopes, the challenge of solving this ill-posed inverse problem persists. Recent breakthroughs have introduced innovative algorithms, featuring constrained nonlinear optimization and Bayesian inference, as potential solutions. The Event Horizon Telescope (EHT) Collaboration's endeavors in scrutinizing image reconstructions have offered valuable insights. Yet, when dealing with active galactic nuclei, existing methods encounter a time-consuming obstacle: the need for large and expensive surveys, each with different optimization parameters. In a new publication led by the MPIfR researcher Hendrik Müller, together with Alejandro Mus from the Universitat de València in Spain and Andrei Lobanov from the MPIfR, they present a groundbreaking solution – a nonconvex, multiobjective optimization approach that opens new avenues. Their methodology leverages a multiobjective version of the genetic algorithm, known as MOEA/D. This genetic algorithm explores the objective function through evolutionary operations, identifying various local minima while avoiding the pitfalls of saddle points. These experiments, utilizing synthetic data based on the 2017 EHT array and a potential future EHT configuration, demonstrate the power of MOEA/D. We successfully unveil a complete Pareto front of nondominated solutions, showcasing the diverse image morphologies. The publication discuss strategies for identifying the most natural guess among these solutions and put it to the test using synthetic data. Finally, they apply MOEA/D to observe the black hole shadow in Messier 87 with the 2017 EHT data. In conclusion, MOEA/D proves to be a flexible and efficient tool, outperforming Bayesian methods in terms of speed and solution exploration. This research comprises the first of two papers, with the first explaining the fundamentals of multiobjective optimization and MOEA/D while demonstrating its capabilities in recovering static images. A further publication will extends the algorithm's utility, enabling dynamic and polarimetric reconstructions, both static and dynamic. More details about the present publication, at the current issue of Astronomy & Astrophysics, is available here.
DoG-HiT: A Breakthrough in High-Resolution Imaging
24 May 2023
A substantial change forward is underway in the field of Very Long Baseline Interferometry (VLBI). With a limited number of antennas and constrained observing time, imaging cosmic phenomena with precision has always been a challenge. However, recent innovations in multiscalar imaging, such as the DoG-HiT method, have changed the game. Known for their speed, accuracy and unbiased performance, these techniques address the sparsity problem in Fourier domain sampling. In a publication written by the MPIfR scientists Hendrik Müller and Andrei P. Lobanov, they introduce a multiscalar approach that extends to polarimetric imaging, dynamically evolving sources, and dynamic polarimetric reconstructions, aptly named "mr-support imaging". By using wavelet transforms and a set of statistically significant coefficients as priors, we've achieved remarkable results. Synthetic data tests with the Event Horizon Telescope (EHT) demonstrate the power of mr-support imaging, providing a rich regularisation for complex dynamics at the event horizon scale. Looking ahead, the ngEHT extension promises even more exciting opportunities for dynamic polarimetric reconstructions. As instruments continue to evolve, the potential to observe dynamically evolving patterns in unprecedented detail grows. This work introduces a simpler but effective regulariser, multiresolution support, to the arsenal of dynamic reconstruction methods. More details can be found at the present issue of Astronomy & Astrophysics, here.
First image of a black hole expelling a powerful jet
Selected press coverage
Articles derived from the Nature paper and the related press releases
A Fresh View of an Increasingly Familiar Black Hole (Dennis Overbye), The New York Times, 26 April 2023
Black-hole image reveals details of turmoil around the abyss (Davide Castelvecchi), Nature, 26 April 2023
Testing Gravity with Black Holes: Can we tell them apart?
16 March 2023
A team of researchers led by the PhD candidate Jan Röder at the MPIfR has used computer simulations to test their ability to distinguish between two theories of gravity under different accretion and emission scenarios. They carried out 3D simulations of two black holes, one based on the Kerr solution to general relativity and the other on ton a branch of solutions to Einstein-Maxwell-dilaton-axion gravity, the dilaton black hole. Further, they modelled thermal synchrotron emission and applied a non-thermal electron distribution function to compare with multi-wavelength observations. The study found that differences between the two black hole spacetimes are not always distinguishable with current observational technology, and that the choice of emission model has a greater effect on the spectra than the accretion model or the choice of spacetime. More information is available directly at the publication in the last issue of Astronomy and Astrophysics, here.
Radio dynamics of the binary black hole candidate OJ 287 from Effelsberg monitoring
23 February 2023
In a new study from the MOMO program, addressing the multifrequency radio variability of the blazar OJ 287 from 2015 to 2022, led by Stefanie Komossa from the MPIfR, data covering a wide range of activity states and employs data spanning from 2015 to 2022, complemented by Fermi γ-ray observations, are presented. The team of researchers employ techniques such as discrete correlation functions to analyse the data. The connection between the radio emissions and the multiwavelength radiation is explored in great detail. Fascinatingly, they discover deep fades in both radio and optical-UV fluxes that recur every 1-2 years. However, one of the most intriguing findings is the absence of a precursor flare of thermal bremsstrahlung, as predicted by one of the binary supermassive black hole models for OJ 287. This raises questions about the prevailing understanding of this blazar's behavior. The study also focuses on the remarkable 2016/2017 nonthermal outburst initially detected with Swift, shedding light on its nature. The authors propose that this outburst represents the latest occurrence of the famous optical double-peaked outbursts of OJ 287, favoring binary scenarios that do not require a highly precessing secondary supermassive black hole. For more details on this research, check out the full publication in the Astrophysical Journal here.
General relativity and the twinkling of Sgr A* in Infrared and X-Ray light
18 January 2023
An international team of astronomers led by Sebastiano von Fellenberg at the MPI für Radioastronomie has studied the supermassive black hole at the center of the Milky Way, called Sagittarius A*. Astronomers have observed occasional bright flares of near-infrared and X-ray light. These flares are thought to come from the black hole's innermost accretion flow. By analyzing data from the Spitzer and Chandra observatories, the researchers identified 25 near-infrared and 24 X-ray flares. Using a computer program that takes into account the effects of general relativity, the researchers modeled the trajectories of "hot spots" and examined the light curves of the flares for signs of these effects. They found that, despite their varying shapes, all flares share a common, exponential impulse response. This impulse response is symmetric, meaning that the rise and fall times are the same, and has an exponential time constant of about 15 minutes. The researchers determined that the characteristic flare shape is not consistent with hot-spot orbits viewed edge-on, and were able to estimate the inclination of the orbital plane of the hot spots with respect to the observer (about 30 degrees, but less than 75 degrees) and the characteristic timescale of the intrinsic variability (a few tens of minutes).
More information, at the original publication in the Astronomy & Astrophysics journal, here.
Journey to the Heart of a Cosmic Beast: Uncovering the Connection Between Radio Waves and Gamma Rays in 3C 84
03 January 2023
A team of radio astronomers, led by the young scientist Georgios F. Paraschos at the MPI für Radioastronomie, has studied the conection between the high-energy and the radio emission in the nearby quasar 3C 84. The team compared the radio and gamma-ray light curves of 3C 84 (aka NGC 1275) to understand how its jets are formed. By analyzing the time differences between the flares seen in these light curves, they found that the energy of the particles and magnetic fields in the jets are balanced. They also determined the location of the "jet apex" and found that the gamma-ray emission is related to the radio emission. Additionally, the team led by Dr. Paraschos calculated two parameters that describe the properties of the jet, and the results are consistent with a mechanism proposed in 1977 by Blandford and Znajek for jet formation. These findings provide new insights into the mysterious and complex processes that drive the formation and evolution of cosmic jets.
More information at the original publication in the Astronomy & Astrophysics journal, here.
A novel multiscale imaging approach for radio interferometry: DoG-HiT
19 October 2022
A new algorithm for imaging interferometric data has been developed by MPIfR astronomers Hendrik Müller and Andrei P. Lobanov, based on a multiscale wavelet deconvolution algorithm, DoG-HiT, for imaging sparsely sampled interferometric data. The method combines the difference of Gaussian (DoG) wavelets and hard image thresholding (HiT). DoG-HiT is a stable method and benchmark its performance against image reconstructions made with the CLEAN and regularized maximum-likelihood (RML) methods using synthetic data. The comparison shows that DoG-HiT matches the super-resolution achieved by the RML reconstructions and surpasses the sensitivity to extended emission reached by CLEAN. Further details of this algorithm can be found the publication presented in the latest issue of Astronomy & Astrophysics, available here.
A comprehensive summary of the VLBI analysis software, presented to the community
10 October 2022
Very-long-baseline interferometry (VLBI) is a challenging observational technique, which requires in-depth knowledge about radio telescope instrumentation, interferometry, and the handling of noisy data. The reduction in raw data is mostly left to the scientists and demands the use of complex algorithms implemented in comprehensive software packages. The correct application of these algorithms necessitates a good understanding of the underlying techniques and physics that are at play. The verification of the processed data produced by the algorithms demands a thorough understanding of the underlying interferometric VLBI measurements. A review led by MPIfR scientist Michael Janßen, also contributed by Jan Wagner from our institute describes the latest techniques and algorithms that scientists should know about when analyzing VLBI data. This work is published in the present issue of the scientific journal Galaxies, see here.
Unlocking the secrets of 3C 84's powerful jet
31 August 2022
An international team of scientists led by Georgios F. Paraschos from the MPI für Radioastronomie has studied the radio galaxy 3C 84 for over two decades to understand its powerful jets. By using advanced telescopes, researchers were able to produce high-resolution images of the jet's inner core region and determine the kinematics of its ejected features. They found that the jet features travel at speeds between 0.055 and 0.22 times the speed of light and their ejection times coincide with changes in radio and gamma-ray emissions. The scientists also discovered that the jet's width varies with frequency, which suggests that it has a stratified structure. The findings provide insights into the jet's origin and how it evolves over time.
More information, at the publication in the present issue of the Astronomy & Astrophysics journal, here.
How is giant radio galaxy NGC 315's accretion disk powering Its jet?
26 August 2022
A team of astronomers led by Luca Ricci from the MPI für Radioastronomie has studied the properties of a giant radio galaxy, NGC 315, to better understand how the jets seen in active galactic nuclei are powered. Astronomers looked at data from different time periods and frequencies to analyze the source maps and used theoretical models to link the properties of the jet to the physical state of the accretion disk. We found that the bulk flow in NGC 315 accelerates on sub-parsec scales, and this fast acceleration can be explained by magnetism. They also observed a region with a very steep spectral behavior, which indicates that the black hole of NGC 315 is rotating fast and the magnetic flux threading the accretion disk is in excellent agreement with that expected in the case of a magnetically arrested disk (MAD). Using a new technique, they modeled the magnetic field downstream of a quasi-parabolic accelerating jet and reconstructed it up to the event horizon radius. In the MAD scenario, we compared it with the expected magnetic saturation strengths in the disk, finding a good agreement.
More information, at the present issue of the Astronomy & Astrophysics journal, here.
A closer look at the young stars at the galactic center
May 12, 2022
A work led by the MPIfR scientist Maciek Wielgus shows how umerical simulations of accretion discs around a stellar-mass black hole reveal their stratified, elevated vertical structure.These are referred as puffy discs. The work discusses the observational properties of puffy discs, particularly the geometrical obscuration of the inner disc by the elevated puffy region at higher observing inclinations, and collimation of the radiation along the accretion disc spin axis, which may explain the apparent super-Eddington luminosity of some X-ray objects. Synthetic spectra are presented, showing that they are qualitatively similar to those of a Comptonized thin disc. The work suggests that puffy discs may correspond to X-ray binary systems of luminosities above one third of the Eddington luminosity in the intermediate spectral states. The results are published in the present issues of the journal Monthly Notices of the Royal Astronomiccal Society, for more information see here.
EHT Image of the Black Hole in SgrA* - MPIfR scientists tell the story
This time we have insight information, emotional thoughts, and exciting scientific news collected by the Event Horizon Telescope (EHT) Collaboration members at the Max Planck Institute for Radio Astronomy in Bonn, Germany. It has been a great, devoting journey since Sagittarius A* was observed by the EHT in 2017. Our colleagues tell their side of the story.
Created by Joana A. Kramer & Luca Ricci, MPI für Radiastronomie
Astronomers reveal first image of the black hole at the heart of our galaxy - Event Horizon Telescope Official Press Release
Astronomers reveal first image of the black hole at the heart of our galaxy - European Southern Observatory Official Press Release
Today, at simultaneous press conferences around the world, including at the European Southern Observatory (ESO) headquarters in Germany, astronomers have unveiled the first image of the supermassive black hole at the centre of our own Milky Way galaxy. This result provides overwhelming evidence that the object is indeed a black hole and yields valuable clues about the workings of such giants, which are thought to reside at the centre of most galaxies. The image was produced by a global research team called the Event Horizon Telescope (EHT) Collaboration, using observations from a worldwide network of radio telescopes.
Press Conference at ESO on new Milky Way results from the EHT team, followed by a public Q&A event
The ESO Director General delivered the opening words. EHT Project Director Huib Jan van Langevelde and EHT Collaboration Board Founding Chair Anton Zensus delivered remarks. A panel of EHT researchers including Thomas P. Krichbaum (MPIfR) and Christian Fromm (Univ. Würzburg, also affiliated with the MPIfR) explained the result and answer questions from journalists.
Following the press conference, at 16:30 CEST ESO hosted an online event for the public via this same streaming link: a live question and answer session where members of the public will have the opportunity to query another panel of EHT experts (which include also Michael Janssen from the MPIfR).
Selected press coverage
For the German-speaking reporting, go to our area in German language.
The Milky Way’s Black Hole Comes to Light, The New York Times (Dennis Overbye), 12 May 2022
The history of Sagittarius A*, the Milky Way's supermassive black hole, Astronomy.com, Paul Sutter, 12 May 2022
See The Jaw-Dropping First Image Of The Black Hole At The Heart Of Our Galaxy Just Revealed By Astronomers, Forbes (Jamie Carter), 12 May 2022
Svelata la prima immagine del buco nero al centro della Via Lattea, La Repubblica (Matteo Marini), 12 May 2022
Captan la primera imagen del agujero negro de nuestra galaxia, Sagitario A*, probando su existencia, El Mundo (Ángel Díaz & Teresa Guerrero), 12 May 2022
Primera imagen de Sagitario A*, el agujero negro del centro de la Vía Láctea, La Vanguardia (Josep Corbella), 12 May 2022
What you need to know about the Sagittarius A* black hole photo, BBC (Sara Rigby), 16 May 2022
First-ever image of the black hole ‘shadow’ at the heart of the Milky Way revealed by the Event Horizon Telescope, Physics Workd, 12 May 2022
How high-energy particles shape the appearance of M87: a new study
20 April 2022
An international team of astronomers led by Christian M. Fromm, affiliated to the MPI für Radioastronomie, as well as to the Universities of Würzburg and Frankfurt, presents a new study in the present issue of Astronomy & Astrophysics. Based on the previous work from the Event Horizon Telescope, which captured images of the innermost emission of the M87 galaxy, revealing a ring-like structure surrounding a supermassive black hole. However, at lower frequencies, the galaxy had a large-scale jet emitting non-thermal energy. To better understand these observations, the team led by Dr. Fromm used simulations to model the accretion of magnetized plasma onto black holes and jet launching. They were able to model the observed broad-band spectrum of M87 and fit the structure of the jet using simulations that included a mixture of thermal and non-thermal particle distributions. These results provide new insights into the behavior of black holes and the surrounding material.
More information is available at the original publication here.
The collimation in the twin jet of NGC 1052
09 February 2022
The radio galaxy NGC 1052 has been explored in the innermost regions of its dual jet by means of radio interferometr. An international team of radio astronomers led by Dr. Anne-Kathrin Baczko from our institut shows that the jet presents a clear transition in the collimation profile at 10 000 gravitational radii, with an upstream parabolic shape, which turns into conical downstream. At about 1 000 gravitational radii, the jet has an opening angle of about 30°. These results show that the approaching (eastern) and receding (western) show a somewhat different emission, for which the receding jet emission my be affected by an absorption cloud of gas in the line of sight. More information is available at the original publication in the journal Astronomy & Astrophysics, available here.
Blazar 0716+714 flaring from the radio through the gamma-ray sky
26 January 2022
An international team of astronomers led by DaeWon Kim from the MPI für Radioastronomie have studied blazar 0716+714, more specifically its jet. They used radio waves and gamma rays to create a picture of how the jet behaves. Over a period of ten years, they found that there were times when the radio and gamma rays were closely linked, and other times when they were not. They discovered that the gamma rays were being produced by multiple regions in the jet, upstream from where the radio waves were being produced. They were also able to identify different parts of the jet moving at different speeds, and they found that the brightness of the jet decreased as it got further from the center. Interestingly, the researchers noticed that the times when the radio and gamma rays were closely linked coincided with times when the jet was pointing in a specific direction. They suggest that a moving disturbance, like a shockwave, passing through the radio core and the direction of the jet could be causing the correlation between the radio and gamma rays. Overall, this study helps us understand how these distant objects behave and provides insight into the complex processes that create the emissions we observe.
More details on the work are presented in the present issue of The Astrophysical Journal, here.
Computing polarised jet emission
15 December 2021
A publication presented by Joana A. Kramer, PhD candidate at the MPIfR together with her supervisor, Nicholas R. Macdonald, shows that jet emission is edge-brightened when the magnetic field is toroidal in nature and spine-brightened when the magnetic field is poloidal in nature. Additionally, the circularly polarized emission exhibits both negative and positive sign for the toroidal magnetic field morphology. Last but not least, the relativistic jet's emission is largely independent of different emission scaling relations when the ambient medium is excluded. This is based in numerical simulations performed in 3D including relativistic, magnetohydrodynamic effects (PLUTO code), and synthetic images created from these virtual jets (using the RADMC-3D code, which can reproduce the polarised emission of light coming from its energetic, black-hole-powered plasma. More details are available in the present issue of Astronomy & Astrophysics, at this publication.
Press release by the Max Planck Society headquarters: Zoom into the dark heart of Centaurus A
The Event Horizon Telescope takes a close-up of the nearest radio galaxy
EHT Pinpoints Dark Heart of the Nearest Radio Galaxy, Event Horizon Telescope
EHT Collaboration Press Release on 19 July 2021
Press echo
English
A deep look at a nearby galaxy's black hole reveals the launching point of intergalactic jets, Phil Plait, Bad Astronomy blog at SyFy Wire, 19 July 2021
The amazing Event Horizon Telescope has done it again: It has taken extraordinarily high-resolution images of the nearby galaxy Centaurus A, revealing twin beams of material shooting away from the supermassive black hole in its heart at a significant fraction of the speed of light.
Event Horizon Telescope captures ‘beautiful’ images of second black hole’s jet, Daniel Clery, Science Magazine, 19 July 2021, quoting Michael Janssen
The astronomy team that 2 years ago captured the first close-up of a giant black hole, lurking at the center of the galaxy Messier 87 (M87), has now zoomed in on a second, somewhat smaller giant in the nearby active galaxy Centaurus A. The Event Horizon Telescope’s (EHT’s) latest image should help resolve questions about how such galactic centers funnel huge amounts of matter into powerful beams and fire them thousands of light-years into space. Together the images also support theorists’ belief that all black holes operate the same way, despite huge variations in their masses.
Event Horizon Telescope Reveals Curious Jet Structure from Black Hole, Camille M. Carlisle, Sky & Telescope, 20 July 2021, quoting Michael Janssen
Observations of the nearest radio galaxy, Centaurus A, provide the highest-resolution look at the long jets shooting from the galaxy’s supermassive black hole.
After capturing first photo of a black hole, Event Horizon Telescope zooms in on a second (Jackson Ryan), c|net, 20 July 2021, quoting Michael Janssen
From the telescope that brought you hits like The First Black Hole Photo comes the best look yet at extreme cosmic jets.
German:
Der Jet aus dem Herzen des Monsters, Franziska Konitzer, Spektrum, 19 July 2021
Schwarze Löcher verhalten sich ähnlich, Rainer Kayser, Welt der Physik, 19 July 2021, quoting Michael Janssen
In den Zentren der meisten Galaxien befindet sich ein Schwarzes Loch mit der millionen- oder gar milliardenfachen Masse unserer Sonne. Einen Blick in die unmittelbare Nähe dieser supermassereichen Objekte zu werfen, war lange nicht möglich. Erst mit dem Event Horizon Telescope, einem Zusammenschluss von Radioteleskopen in aller Welt, gelang die erste Aufnahme eines supermassereichen Schwarzen Lochs. Nun richteten Astronomen den Fokus auf das Zentrum der 13 Millionen Lichtjahre entfernten Radiogalaxie Centaurus A. Die Beobachtungen legen nahe, berichtet das Team jetzt im Fachblatt „Nature Astronomy“, dass sich Schwarze Löcher über einen weiten Massenbereich ähnlich verhalten.
Spanish:
El corazón de la galaxia Centaurus A observado con un detalle sin precedentes, Agencia Efe, 19 July 2021
La galaxia Centaurus A ha sido estudiada con un detalle sin precedentes por el Telescopio Horizonte de Sucesos (EHT), lo que ha permitido ubicar el agujero negro supermasivo que hay en su centro y detectar que de él está surgiendo un chorro gigantesco.
Un estudio que publica hoy Nature Astronomy y firmado por un equipo internacional, destaca que lo más sorprendente de las observaciones es que los bordes exteriores de chorro parecen emitir radiación, lo que desafía los modelos teóricos sobre este tipo de fenómenos.
EHT imaging of Centaurus A: A conversation with Nature Astronomy and Michael Janssen (and also the MPIfR alumni Sera Markoff and Marios Karouzos)
The cosmic battery powers galaxy halo magnetic fields
20 May 2021
A publication by the MPIfR-affiliated astronomer Ioannis Myserlis and his colleague Ioannis Contopoulos (Athens) reveals, appeared today at the Astronomy & Astrophysics journal, postulates a universal mechanism to explain the magnetic fields in galactic halos. The author have studied thirty-five nearby edge-on spiral galaxies from the Extended Very Long Array Survey named Continuum HAlos in Nearby Galaxies – an EVLA Survey (CHANG-ES), and detected large-scale magnetic fields in sixteen of them. The authors used radio polarization data to create Faraday rotation measure maps for all galaxies in the sample and stack them with the aim of amplifying any underlying universal toroidal magnetic field pattern in the halo above and below the disk of the galaxy. The presented work discovered a large-scale magnetic field in the central region of the stacked galaxy profile, which is attributable to an axial electric current that universally outflows from the center, both above and below the plane of the disk. A similar symmetry-breaking has also been observed in astrophysical jets, but never before in galaxy halos. This is an indication that galaxy halo magnetic fields are probably not generated by pure magnetohydrodynamic processes in the central regions of galaxies. One such promising physical mechanism is the Cosmic Battery operating in the innermost accretion disk around the central supermassive black hole. More details of this work can be found in the original publication here.
Einstein's Theory Can Explain the Black Hole M87*
20 May 2021
Event Horizon Telescope Collaboration scientists including MPIfR researchers use data which produced the first image of a black hole to constrain its fundamental properties.
In 2019, the EHT Collaboration published the first image of a black hole located at the centre of the galaxy M87. Now a collaboration team led by theoretical physicists at the Goethe University Frankfurt and with the participation of the MPIfR EHT team have analysed data from the black hole M87* to test Albert Einstein's theory of general relativity. According to the tests, the size of the shadow from M87* is in excellent agreement with a black hole predicted by general relativity, but narrows the properties of black holes in other theories down. These results are presented in today’s issue of the Physical Review D journal.
Constraining black hole models with EHT observations | Event Horizon Telescope
Einstein's Theory Can Explain the Black Hole M87*
X-ray studies from the binary black hole candidate OJ 287
05 May 2021
A new study of the quasar OJ 287, led by the MPI für Radioastronomie scientist Stefanie Komossa, presents results from spectroscopic observations performed between 2005 and 2020. In the long period of study, the galaxy nucleus presents extreme activity minima and outbursts. The X-ray spectrum of the source can be decomposed into three components: low-state emission consisting by Inverse Compton photons, super-soft synchrotron emission becoming dominant as the source brightens, and an additional outburst component with intermediately-soft photons. The publication discuss in detail the postulated black hole binary nature (having the primary black hole a mass of 18 billion solar masses) of the central region and the X-ray results. More details can be found at the original publication, presented at the latest issue of Monthly Notices of the Royal Astronomical Society.
Challenging the radio galaxy classification with the VLA-COSMOS survey at 10 cm wavelength
20 April 2021
An international team of astronomers led by Eleni Vardoulaki (affiliated to the MPI für Radioastronomie, at present at the Thüringer Landessternwarte in Tautenburg) has studied a sample of faint radio galaxies down to μJy levels with the 15-GHz sample of the VLA-COSMOS survey. Radio active galactic nuclei (AGN) are traditionally separated into two Fanaroff-Riley (FR) type classes, edge-brightened FRII sources or edge-darkened FRI sources. This dichotomy is becoming too simplistic in linking the radio structure to the physical properties of radio AGN, their hosts, and their environment. The work by Vardoulaki and collaborators approached the study of these galaxies both measured by a machine-learning algorithm and also by hand, following a parametric approach to the FR classification. Different physical parameters were estimated, as well as the galaxy host properties. The work shows a broad distribution and overlap of Fanaroff-Riley radio galaxies and jet-less/compact radio active galactic nuclei populations. The results point to the need for a different classification scheme, that expands the classic classification by taking into consideration the physical properties of the objects rather than their projected radio structure which is frequency-, sensitivity- and resolution-dependent.
These results are presented in the last issue of the journal Astronomy & Astrophysics, see the original publication here.
RadioAstron reveals the complex structure in the jet of quasar 3C 345
14 April 2021
A team of radio astronomers led by the MPIfR astrophysicist Felix M. Pötzl has studied the innermost jet morphology and magnetic field strength in the active galactic nucleus (AGN) 3C 345 with an unprecedented resolution using images obtained within the framework of the key science programme on AGN polarisation of the Space VLBI mission RadioAstron. The results analyze images obtained at a wavelength of 21 cm on 2016 March 30 with RadioAstron and eighteen ground-based radio telescopes. The obtained images reveal a complex jet structure a resolution corresponding to a projected linear scale of about 2 pc or a few thousand gravitational radii. This work identfies the synchrotron self-absorbed core at the jet base and find a brightest feature in the jet several parsecs downstream of the core. The work also studies the linearly polarised emission, which is related to the magnetic field distribution in the jet, and the intrinsic brightness of the source and its information about the source physics (via the so-called brightness temperature).
Additional information can be obtained at the original publication here.
Zoom Out of the Black Hole M87*
Beginning with the EHT’s now iconic image of M87, a new video takes viewers on a journey through the data from each telescope. Each step provides data across many factors of ten in scale, both of wavelengths of light and physical size.
A swing in the jet direction at the quasar 3C 273
24 March 2021
The high-redshift radio source with number 273 in the third Cambridge catalog (also known as 4C +02.32, ON 044, or CTA 053) is one of the best studied objects in very-long-baseline interferometry. New results presented in a publication led by the Bonn astronomer Misha Lisakov reveals changes in the polarisation of the jet which suggest a change in the jet direction during the period 2009-2010 from multi-wavelength studies using the Very Long Baseline Array. The work, presented in the latest issue of The Astrophysical Journal, shows that the jet Faraday rotation measure has changed significantly toward negative values compared with that previously observed. These changes could be explained by a swing of the parsec-scale jet direction, which causes synchrotron emission to pass through different portions of the Faraday screen. The work develops a model for the jet-sheath system in 3C 273 where the sheath is wider than the single-epoch narrow relativistic jet. The wide jet–sheath boundary is about 750 light years downstream from its beginning. Most of the Faraday rotation occurs within the innermost layers of the sheath. Further details on the jet parameters and the impact of this work in the study of other sources can be obtained in the original publication, see here.
Zoom into the Magnetized Black Hole M87* | Event Horizon Telescope
The Black Hole M87* Seen Through a Polarizer | Event Horizon Telescope
How Magnetic Fields Affect Black Hole Images | Event Horizon Telescope
Official EHT Press Release: Astronomers Image Magnetic Fields at the Edge of M87’s Black Hole (quoting, among others MPIfR alumnus Iván Martí-Vidal from the Univ. València)
The Event Horizon Telescope (EHT) collaboration, who produced the first ever image of a black hole, has revealed today a new view of the massive object at the centre of the M87 galaxy: how it looks in polarised light. This is the first time astronomers have been able to measure polarisation, a signature of magnetic fields, this close to the edge of a black hole. The observations are key to explaining how the M87 galaxy, located 55 million light-years away, is able to launch energetic jets from its core.
Media Echo
English
Astronomers detct strong magnetic fields around M87's black hole, Camille M. Carlisle, Sky & Telescope, 24 March 2021
Event Horizon Telescope data support the idea that magnetic fields control how black holes feed and grow.
Mysterious swirling light gives new insights into black holes, Linda Geddes, The Guardian, 24 March 2021
Scientists reveal first EVER photo of a supermassive black hole in polarised light: M87's galactic centre is caught on camera and could help to explain how the stellar phenomenon 'eats' matter, Ryan Morrison, Daily Mail, 24 March 2021
The supermassive black hole at the centre of the galaxy M87 is more than 6.5 billion times the mass of the sun. Astronomers used the Event Horizon Telescope to capture the sensational new images of the massive object. The black hole was the first to be directly imaged by astronomers and this new image is from the same data. The new image allowed the astornomers to measure polarisation from the light surrounding the black hole.
The Most Intimate Portrait Yet of a Black Hole, Dennis Overbye, The New York Times, 24 March 2021
Two years of analyzing the polarized light from a galaxy’s giant black hole has given scientists a glimpse at how quasars might arise.
Global telescope creates exquisite map of black hole’s swirling magnetic field, Alison Kiesman, Astronomy, 24 March 2021
The Event Horizon Telescope’s newest images of M87’s supermassive black hole hint at how its jets are fired far into space.
Magnetic Field around a Black Hole Mapped for the First Time, Stephanie Pappas, Scientific American, 24 March 2021
Images from the Event Horizon Telescope reveal new details of how supermassive black holes produce huge jets of matter and energy.
New picture of famous black hole reveals its swirling magnetic field, Leah Crane, New Scientist, 24 March 2021
The first picture of a black hole’s shadow just got even more interesting. The Event Horizon Telescope (EHT) collaboration released the first direct image of a black hole in 2019, and while the picture on its own was impressive, it wasn’t the scientific smorgasbord some had hoped for. Now, researchers have added polarised light to the picture, giving us an idea of how magnetic fields around a supermassive black hole create powerful jets of matter.
Event Horizon Telescope sees the Magnetic Engine behind a Supermassive Black Hole's Immense Power, Phil Plait, Bad Astronomy, 24 March 2021
In 2019, astronomers stunned the world, releasing an epic image of material swirling around the supermassive black hole in the core of the galaxy M87 55 million light years from Earth. They connected radio telescopes from around the planet to create the Event Horizon Telescope, a virtual telescope mimicking the power of a telescope the size of our planet, to achieve this amazing observation.
German
Schwarzes Loch: Warum ein Monster im All Materie ausspuckt, Johannes Magnus, Rhein-Zeitung, 31 March 2021, quoting J.A. Zensus
Acht riesige Radioteleskope beobachteten 2017 vier Tage lang gemeinsam ein Monster im All: das Schwarze Loch inmitten der fernen Galaxie M87. 55 Millionen Jahre lang waren die Licht- und Radiowellen von dort bis zur Erde gereist, wo sie eingefangen wurden. Die Daten der Teleskope wurden zwei Jahre lang mit Supercomputern zusammengerechnet und überprüft. Dann präsentierten die Astronomen der Menschheit das erste Bild eines Schwarzen Lochs. Nun haben sie den Daten weitere Einzelheiten entlockt und entdeckten gigantische Magnetfelder um den kosmischen Giganten.
Schwarzes Loch in der Galaxie M87: Forschende machen Magnetfelder sichtbar – „Schlüssel zum Verständnis“, Tanja Banner, Frankfurter Rundschau, 31 March 2021
Das erste schwarze Loch, das von Forschenden fotografiert wurde, sorgt erneut für Aufsehen: Ein Forschungsteam hat nun seine Magnetfelder untersucht.
Forscher machen Magnetfelder nah an Schwarzem Loch sichtbar, Wochenblatt.de, 30 March 2021, quoting J.A. Zensus
Das erste Bild eines schwarzen Lochs, das von Forschenden fotografiert wurde, sorgt bereits 2019 für Aufsehen: Nun haben die Experten seine Magnetfelder unter die Lupe genommen.
Erstmals Magnetfelder am Rand eines Schwarzen Lochs gemessen, Der Standard, 27 March 2021, quoting J.A. Zensus
Vor zwei Jahren konnte erstmals der Schatten eines Schwarzen Lochs fotografiert werden. Jetzt entdeckten Forscher dort polarisierte Radiostrahlung.
Schwarzes Loch in polarisiertem Licht, Welt der Physik, 24 March 2021
Am 10. April 2019 veröffentlichten Wissenschaftler das allererste Bild eines Schwarzen Lochs, das eine helle ringförmige Struktur mit einer dunklen zentralen Region – dem Schatten des Schwarzen Lochs – zeigt. Die zugrunde liegenden Daten, gesammelt mit dem Event Horizon Telescope, hat die Kollaboration seither noch eingehender untersucht. Ein signifikanter Anteil des Lichts um das supermassereiche Objekt im Zentrum der Galaxie M87 ist demnach polarisiert. Und das zeige deutlich, dass der Ring um das Schwarze Loch magnetisiert ist, berichtet das Team nun in zwei separaten Artikeln in der Fachzeitschrift „The Astrophysical Journal Letters“.
Erster Blick auf Magnetfelder am Schwarzen Loch, Nadja Podbregar, Wissenschaft.de, 24 March 2021
Im April 2019 sorgte das erste Foto eines Schwarzen Lochs für weltweites Aufsehen. Jetzt zeigt das Event Horizon Telescope (EHT) weitere Details des supermassereichen Schwarzen Lochs im Zentrum der Galaxie M87. Denn erstmals haben die Astronomen auch die Polarisation des Lichts gemessen, das direkt am Rand des Schwarzen Lochs frei wird. Diese Schwingungsrichtung des Lichts liefert wertvolle Informationen über die Magnetfelder im Umfeld eines solchen Schwerkraftgiganten und könnte erklären, wie es dieser aktive Galaxienkern schafft, extrem energiereiche Strahlen- und Materiejets zu erzeugen.
Aufnahme des Schwarzen Lochs von M87: Polarisiertes Licht verrät Magnetfelder, Martin Holland, heise.de, 24 March 2021
Die erste direkte Aufnahme des Ereignishorizonts eines Schwarzen Lochs enthält noch Überraschungen: Das Licht macht die Magnetfelder vor Ort sichtbar.
Magnetfelder im Vorhof der Hölle, Robert Gast, Spektrum der Wissenschaft, 24 March 2021
2019 blickte die Menschheit direkt in das Schwarze Loch im Herzen der Galaxie M87. Nun haben Forscher neue Details aus der weltberühmten Aufnahme herausgeholt.
Das Schwarze Loch offenbart neue Geheimnisse, Sibylle Anderl, Frankfurter Allgemeine Zeitung, 24 March 2021
2019 war es das eindrucksvollste Wissenschaftsbild: Die erste Aufnahme eines Schwarzen Lochs, aufgenommen mit einem erdumspannenden Teleskopverbund. Nun hat es ein Upgrade erhalten.
Auf der Spur der kosmischen Fackel, Jörg Römer, Der Spiegel, 24 March 2021
Forscher haben das erste Bild eines schwarzen Lochs neu ausgewertet. Dabei kamen sie dem Ursprung von mächtigen Plasmastrahlen so nah wie nie zuvor.
Forscher machen Magnetfelder nah an Schwarzem Loch sichtbar, Süddeutsche Zeitung (dpa), 24 March 2021, quoting J.A. Zensus
Vor rund zwei Jahren veröffentlichten Forscher zum ersten Mal das Bild eines Schwarzen Loches. Nun sind sie bei der genaueren Untersuchung des Schwerkraftmonsters in der weit entfernten Galaxie Messier 87 (M87) einen weiteren Schritt vorangekommen.
French
Le trou noir géant M87 commence à livrer ses secrets, Le Figaro, 25 March 2021
Le 10 avril 2019, une collaboration d'astronomes internationale avait montré le premier cliché d'un trou noir, au cœur de la galaxie M87.
Voici à quoi ressemble le champ magnétique au bord du trou noir M87*, Nelly Lesage, Numerama, 24 March 2021
La collaboration de l'Event Horizon Telescope a obtenu une nouvelle image importante du trou noir M87*. Elle est réalisée en lumière polarisée, ce qui offre un aperçu unique du champ magnétique aux abords du trou noir.
Spanish
Primera observación del campo magnético circundante a un agujero negro, Ignacio Crespo, La Razón, 25 March 2021
Haber obtenido una imagen del campo magnético de las inmediaciones de un agujero negro podría ayudar a entender los grandes chorros emitidos por este.
Observan por primera vez los campos magnéticos de un agujero negro, Rafael Ordóñez, El Independiente, 24 March 2021
El Telescopio del Horizonte de Sucesos (EHT), que produjo la primera imagen de un agujero negro, ha revelado hoy una nueva vista del objeto masivo en el centro de la galaxia Messier 87 (M87). Se trata de un nuevo hito en la observación astronómica al analizar, en luz polarizada, el agujero negro supermasivo.
Una nueva imagen permite observar por primera vez el 'borde' de un agujero negro, José Manuel Nieves, ABC, 24 March 2021
Es la primera vez que se consigue fotografiar el agujero negro M87 en luz polarizada, lo que permitirá comprender la naturaleza de los enormes chorros de energía que surgen del corazón de la galaxia.
Una nueva imagen de un agujero negro, Ernesto Lozano Tellechea, Investigación y Ciencia, 24 March 2021
La colaboración EHT obtiene las primeras imágenes en luz polarizada de un agujero negro. El hito permite reconstruir el campo magnético en las inmediaciones del objeto y aporta pistas clave para entender cómo se comporta la materia caliente que lo rodea.
Se observan los campos magnéticos en el borde del agujero negro de la galaxia M87, desQbre, 24 March 2021, quoting MPIfR alumnus Iván Martí-Vidal (Univ. València)
La colaboración del Telescopio del Horizonte de Sucesos (EHT por sus siglas en inglés), que produjo la primera imagen de un agujero negro, ha revelado hoy una nueva perspectiva del objeto masivo en el centro de la galaxia M87: cómo se ve en luz polarizada. Se trata de la primera vez que los astrónomos han podido medir polarización, la “firma” de los campos magnéticos, tan cerca del borde de un agujero negro. Las observaciones son clave para explicar cómo la galaxia M87, ubicada a 55 millones de años luz de distancia, puede lanzar chorros de material muy energéticos desde su núcleo.
A ring accelerator to produce neutrinos in a quasar jet?
17 March 2021
An international team of radio astronomers led by Silke Britzen at the MPI für Radioastronomie suggests the connection between the high-energy neutrino production in the quasar PKS 1502+106 with remarkable features in the jet. Their analysis suggests a radio ring structure in the parsec-scale jet that develops with time. Several arc-structures evolve perpendicular to the jet ridge line. The work also finds hints for precession of a curved jet based on kinematic modelling and a periodicity analysis. The atypical ring may be connected to an interaction of the precessing jet with the outflowing material. Energetic neutrinos are most likely produced by proton–proton interaction in the blazar zone, enabled by episodic encounters of the jet with dense clouds, that is, with some molecular cloud in the outer part. These results have been published today for the May 2021 issue of the British journal Monthly Notices of the Royal Astronomical Society. For additional information, see here.
Collimating jets in radio galaxies: the case of NGC 315
11 March 2021
A study presented by a European team led by the MPIfR astronomer Bia Boccardi (head of an Otto Hahn Research Group) today in Astronomy and Astrophysics reveals a zoom in the structure of the powerful jets in this radio galaxy. The double jet in this galaxy shows a remarkable persistence in its direction at very different scales. The collimation, apparently, is already completed in the innermost region (parabolic shape) and is kept for scales much larger than the optical galaxy (conical shape).
The optical nebula hosting the powerful jet has the number 315 in the New General Catalogue (NGC 315). It is an elliptical galaxy in the constellation Pisces. It was discovered on September 11, 1784 by William Herschel. It is also known as HOLM 028A, OB +392, and TXS 0055+300.
Furthermore, Boccardi's work discusses the possibility that relativistic jets are collimated by winds originated by the accretion disk which surrounds the super massive black hole. The study suggests that a powerful external layer in the jets (sheath) stabilizes the inner spine by isolating it from the interstellar medium, so that the jet travels mostly unperturbed to reach the intergalactic medium. These considerations also play a role to define the different types of galaxy, classified as type I (luminosity decreases as the distance from the central galaxy or quasar host increase) or type II (increasing luminosity in the lobes) in 1974. The publication (open access) can be found here.
The monster awakes: galaxy flares after years of silence
28 October 2020
The narrow-line Seyfert 1 galaxy Markarian 335 hosted a very bright X-ray active nucleus which faded since 2007. Observations from the Swift observatory led by S. Komossa at the MPI für Radioastronomie show a sequence of bright and rapid flare events in the X-ray band, after a long "quiet" time. The new activity in the source can be explained by a decrease of the amount of matter between the active nucleus and us, which partially covered the bright emission. The curtain is lifted, and it shows, the "monster" seems to be awake, but was always there. This work is published in the present issue of Astronomy & Astrophysics, see here.
After the footprints of stellar formation: isotope dating of the clouds to the Galactic Centre
23 October 2020
The present issue of the Astronomy & Astrophysical journal reports about spectral-line observations towards the Galactic centre clouds, in a project led by the PhD researcher Pedro Humire. This study shows a drop in the production of massive stars at the Galactic centre, based on measurements of the carbon and sulphur abundances in the interstellar medium. For that different isotopes int he CS molecule were studied (combinations of atomic weight values of 12 and 13 for carbon, and of 32, 33, and 34 for sulphur). Isotopic ratios can be computed for the different species, and the study shows that the decreasing trend in the 32S/34S ends at about 425 light-years from the centre of our galaxy. More details can be checked at the original publication, here.
The connection between gamma rays and radio emission in radio galaxies
23 September 2020
A work presented by R. Angioni from the MPI für Radioastronomie gives new clues on the connection between the low-energy (radio) and the high-energy (gamma) emission in radio galaxies. This is part of a larger work which is presented in a series of publications; the present report focus on prominent radio galaxies in the Southern hemisphere which were not detected by the Fermi/LAT telescope, and gives details on the jet kinematics for several objects. In general, the study shows that high-energy emission from radio galaxies is related to parsec-scale radio emission from the inner jet, but is not driven by relativistic Doppler boosting effects, in contrast to the situation in blazars. The results are presented in the last issue of Astronomy & Astrophysics, for more information see here.
The Wobbling Shadow of the M87* Black Hole
This animation presents about three years in the life of M87*, as predicted by numerical simulations. It shows the expected appearance and dynamics of the supermassive black hole as observed by the EHT. You can see turbulent gas heated to billions of degrees swirling around the event horizon, before finally plunging into the black hole. A sharp bright ring surrounding the black hole shadow is an effect of extremely strong lensing near the so-called photon shell.
The blurred portion of the animation corresponds to the effective resolution of the EHT. The dashed black ring measures 42 microarcseconds in diameter. The clock hand indicates the position of the bright side of the fitted crescent. We expect that the bright side should be most of the time located in the bottom of the image, where the velocity of the rotating gas is pointed in the observer’s direction. However, because of the turbulence, the fitted position angle varies quite a bit - the crescent wobbles. By studying the time-variability of the M87* image with the EHT, we can learn about the physics of matter in an extreme environment very near the event horizon, and understand the relations between the black hole and the accretion flow surrounding it.
Media echo
English
EHT data show turbulence makes the glowing ring around M87’s black hole wobble, Maria Temming, Science News, 23 September 2020
Famous for the first-ever image of a black hole, M87* is now revealing how it changes over time
Surprise! The ring around M87 galaxy's monster black hole wobbles over time, Mike Wall, Space.com, 23 September 2020
The Event Horizon Telescope team is learning about the huge black hole's behavior over the past decade.
History-making black hole seen to do a shimmy, Jonathan Amos, BBC, 23 September 2020, quoting Anton Zensus
When scientists presented the first ever picture of a black hole last year, it was hailed as an extraordinary breakthrough.
Well, now they've reassessed some of the image data that was acquired in the years running up to that historic snapshot. And it gives us some fresh perspectives on the object known as M87*, which has the monster mass of 6.5 billion Suns. One insight is recognising the black hole's brightness flickers over time.
The ring of material around M87's supermassive black hole is changing with time, Phil Plait, Bad Astronomy, SyFy Wire, 23 September 2020
Last year, astronomers revealed a stunning image showing a ring of matter swirling around a supermassive black hole, and a dark hole in the ring representing the black hole’s “shadow.” That iconic image of the black hole represents a week of observations taken in 2017 by the Event Horizon Telescope (EHT), an array of eight telescopes spread across the world, linked together to increase their resolving power. A team of astronomers tackled this hefty project, and found two important things: The size of the ring and the “shadow” didn’t change, but the brightness of the ring did. Not only that, where it was brightest changed, too, and it’s not clear why.
Black Hole Alight in Glitter, James Maynard, medium.com, 23 September 2020, quoting Anton Zensus
The M 87 black hole, the first body of its type ever photographed by astronomers at the Event Horizon Telescope, shows an unusual glitter…
Astrophysicists Release Landmark “Movie” of Wobbling Black Hole, Victor Tangermann, Futurism, 23 September 2020
"If you want to see a black hole evolve over a decade, there is no substitute for having a decade of data."
This weirdly wobbling black hole upends our theories of the universe, Chris Davies, Slash Gear, 23 September 2020
The Giant Black Hole We Imaged For The First Time Now Appears to Be… Glittering, Michelle Starr, Science Alert, 25sep2020, quoting Anton Zensus
Last year, for the first time, the world gazed in collective wonder at an actual direct image of a black hole's shadow. Now, looking back at earlier, more rudimentary images, scientists have found evidence that the ring around M87* has a wobble that makes it look as though it's glittering.
German
Jahrhundertentdeckung M87* - Ring um Schwarzes Riesen-Loch wackelt, Mitteldeutsches Rundfunk, 23 September 2020, quoting Anton Zensus
Das riesige Schwarze Loch M87*, dessen Bild 2019 eine der großen astronomischen Sensationen war, hält immer neue Überraschungen parat. Nun haben Forscher unter Bonner Federführung herausgefunden, dass sein Ring offenbar hin- und herwackelt.
Himmlisches Flackern, Johanes Grolle, Der Spiegel, 23 September 2020, quoting Thomas Krichbaum and Anton Zensus
Ein kreisrunder Schatten, umschlossen von einem lodernden Ring: Vor anderthalb Jahren sorgte das erste Foto eines schwarzen Loches für Furore. Jetzt legen die Radioastronomen mit neuen Details nach.
Das Schwarze Loch in der Galaxie Messier 87 ist die Ruhe selbst – doch drumherum tut sich was, Neue Züricher Zeitung, Christian Speicher, 23 September 2020, quoting Eduardo Ros
Vor einem Jahr gelang Astronomen zum ersten Mal ein Schnappschuss eines Schwarzen Lochs. Ein Vergleich mit älteren Beobachtungen zeigt nun, wie turbulent es in dessen Umgebung zugeht.
Ring um Schwarzes Loch funkelt, Tagesspiegel, Ralf Nestler, 23 September 2020, quoting Thomas Krichbaum and Anton Zensus and MPIfR alumni Matthias Kadler and Reinhard Genzel
Der funkelnde Ring um das Schwarze Loch in Messier 87, Spektrum der Wissenschaft, Andreas Müller, 23 September 2020, quoting Thomas Krichbaum
Event Horizon Telescope: Das Schwarze Loch von M87 funkelt, Martin Holland, heise, 23 September 2020, quoting Thomas Krichbaum
Das Schwarze Loch im Zentrum der Galaxie M87 wurde als erstes direkt abgebildet. Nun haben Forscher aus Archivdaten ermittelt, wie sich das Abbild verändert.
Schwarzes Loch: Ereignishorizont „wackelt“, Nadja Podbregar, ScineXX, 24 September 2020, quoting Anton Zensus
Event Horizon Teleskop zeigt zeitliche Veränderungen am Schwarzen Loch M87*
Schwarze Löcher: Forscher entdecken funkelnden Ring, Constantin Krüger, 24sep2020, quoting Thomas Krichbaum
Ein Koloss im Wandel, Sibylle Anderl, Frankfurter Allgemeine Zeitung, 01 October 2020
Das erste Bild vom Schatten des Schwarzen Lochs im Zentrum der Galaxie M 87 war 2019 eine wissenschaftliche Sensation. Jetzt haben sich die Astronomen des Event Horizon Telescope ältere Beobachtungsdaten angesehen. Sie konnten verfolgen, wie sich der helle Ring des Massenmonsters über mehrere Jahre hinweg verändert hat und zu funkeln scheint.
Russian
Астрономы увидели мерцающую тень черной дыры, РИА Новости, 23 September 2020, quoting Thomas Krichbaum and Anton Zensus
Телескоп горизонта событий увидел колебания яркости тени черной дыры, N+1, 23 September 2020
Коллаборация Телескопа горизонта событий (EHT) опубликовала результаты анализа данных наблюдений за сверхмассивной черной дырой в галактике М87 в течение восьми лет. Ученым удалось подтвердить стабильность диаметра тени, а также увидеть изменения ее яркости, что согласуется с теоретическим предсказаниями. Статья опубликована в журнале The Astrophysical Journal.
Spanish
El primer agujero negro capturado en imagen sufre una evolución turbulenta, El Universal, 23 September 2020
El centro de la galaxia M87 ha revelado una variación de su orientación
El primer agujero negro captado en imagen se tambalea, Europa Press, 23 September 2020
Un análisis de cuatro años de archivos sobre el agujero negro supermasivo en el centro de la galaxia M87, que se logró fotografiar en 2019 en absoluta primicia, ha revelado una evolución turbulenta.
La sombra de M87* se tambalea, y eso sorprende a los científicos, ABC, 23 September 2020
El mismo equipo que hace un año mostró al mundo la primera imagen de un agujero negro ha descubierto que su sombra está «bamboleándose» y ha girado de forma significativa durante los diez últimos años
Nederlaands
Het licht rond het beroemde zwarte gat blijkt te dansen en deinen, George van Hal, de Volkskrant, 24 September 2020
Looking sharper, blobs become filaments: RadioAstron Observations of 0836+710
September 4, 2020
A new study published in the present issue of Astronomy & Astrophysics shows the striking improvement in resolution provided by the space-VLBI mission RadioAstron. The work is based in a study made in the framework of the PhD thesis of Laura Vega-García, performed at the MPI für Radioastronomie. The RadioAstron images reveal a wealth of structural detail in the jet of S5 0836+710 on angular scales ranging from 0.02 mas to 200 mas. Brightness temperatures in excess of 1013 K are measured in the jet, requiring Doppler factors of ≥100 for reconciling them with the inverse Compton limit. Furthermore, several oscillatory patterns are identified in the ridge line of the jet and can be explained in terms of the Kelvin–Helmholtz (KH) instability. For more information, check here.
Binary super massive black hole and jet activity in the quasar OJ 287
27 July 2020
A team of astronomers led by S. Komossa from the MPI für Radioastronomie has observed a very bright X-ray–UV–optical outburst of OJ 287 in 2020 April–June, the second brightest since late 2015. The outburst is predominantly powered by jet emission. The study reports evidence for reprocessing around the iron region in the source core, consistent with an absorption line. If confirmed, it implies matter in outflow at a tenth of speed light. The monitored source brigthness shows multiple episodes of flaring or dipping with a total amplitude of variability of one order of magnitude over the last four years prior to the 2020 outburst. This outburst is consistent with an after-flare predicted by a binary black hole model, where the disc impact of the secondary black hole triggers time-delayed accretion and jet activity of the primary black hole. This work is presented in the latest issue of the British journal Monthly Notices of the Royal Astronomical Society, see the publication here.
High-energy neutrinos originate in black-hole powered jets in active galactic nuclei
May 13, 2020
A team of astrophysicists including Yuri Y. Kovalev, affiliated to the MPI für Radioastronomie and Bessel Award of the Alexander von Humboldt foundation, have come close to solving the mystery of where high-energy neutrinos come from in space. The team compared the data on the elusive particles gathered by the Antarctic neutrino observatory IceCube and on long electromagnetic waves measured by radio telescopes. Cosmic neutrinos turned out to be linked to flares at the centers of distant active galaxies, which are believed to host supermassive black holes. As matter falls toward the black hole, some of it is accelerated and ejected into space, giving rise to neutrinos that then coast along through the universe at nearly the speed of light. These results are published in the last issue of The Astrophysical Journal, see the publication here, and a press release from the Moscow Institute of Physics and Technology here.
Jet shapes in active galactic nuclei dissected: changing from parabolic to conical shape and its physical implications
16 April 2020
A team of astronomers led by Yuri Y. Kovalev from Moscow (Lebedev & MIST), also associated to the MPI für Radioastronomie, has presented a work on ten active galactic nuclei in the close universe (redshift smaller than 0.07) displaying a transition from a parabolic to conical shape. They infer that the geometry transition may be a common effect in AGN jets, and observed only when sufficient linear resolution is obtained. This break occurs at distances of hundred thousand to one million gravitational radii from the nucleus. More in detail, this means that the jet shape transition happens when the bulk plasma kinetic energy flux becomes equal to the Poynting energy flux, while the ambient medium pressure is assumed to be governed by Bondi accretion. In general, the break point may not coincide with the Bondi radius. The results are presented in the online version of the journal Monthly Notices of the Royal Astronomical Society, available here.
EHT zoom into 3C 279 reveals inner structure and jet proper motions
Media coverage on 3C 279 Press Release (selection)
Printed Media
English
April 7, 2020, "Blowtorch of the Gods Captured by Black Hole Image Makers", New York Times, by Dennis Overbye (quoting J.Y. Kim)
Astronomers have given us a look into the engine compartment of a quasar.
Forbes, 2020/04/08, "Beyond the Black Hole: The Event Horizon Telescope Solves a Quasar Mystery We Didn't Know It Existed", by Ethan Siegel (quoting T.P. Krichbaum)
Almost exactly one year ago today, the Event Horizon Telescope collaboration released the first-ever image of a black hole's event horizon. Its publication marked the first time that we'd ever directly detected a region of space where so much matter was concentrated into such a tiny volume that nothing, not even light, could escape from it.
During that same observing campaign, which took place simultaneously across eight different astronomical observatories on Earth, a number of other targets were also imaged, including the quasar 3C 279. With the unprecedented resolution of the Event Horizon Telescope, the origin of this incredibly powerful cosmic jet was revealed for the first time. Although it agrees with what was theoretically predicted, the details are spectacular in an entirely new way.
April 07, 2020, "Event Horizon Telescope spots weird black-hole jet mystery inside quasar", Space.com, by Meghan Bartels (Quoting J.Y. Kim)
At the same time the Event Horizon Telescope was gathering data to create the first-ever image of a black hole, it was also observing an even stranger object.
That object was a quasar, a pair of jets full of super-fast material shooting out from near a supermassive black hole. And the Event Horizon Telescope data suggested that those jets aren't working the way scientists had expected them to, with confusing kinks at their base.
April 07, 2020, Discover, "Event Horizon Telescope Looks Into a Black Hole's Jet", by Alison Klesman (including quotes of J.Y. Kim and J.A. Zensus)
A violent quasar reveals a mystery lurking at its center, thanks to high-resolution images that were never before possible.
April 7, 2020, "Evert Horizon Telescope finds bent jet near black hole", Sky & Telescope, by Camille M. Carlisle (quoting J.Y. Kim)
Observations from the worldwide network of radio telescopes show the fire hose of plasma shooting from a distant galaxy does something strange near its source.
German
April 7, 2020, "Forscher fotografieren erstmals Jet eines Schwarzen Lochs", Süddeutsche Zeitung, by Marlene Weiß (includes quotes of T.P. Krichbaum)
Vor einem Jahr wurde das erste Bild eines Schwarzen Lochs veröffentlicht. Jetzt gibt es ein zweites. Es zeigt Materie, die dem Loch knapp entkommen ist.
Ziemlich genau ein Jahr nachdem das erste direkte Bild eines Schwarzen Lochs um die Welt ging, legen die Forscher von der internationalen Event-Horizon-Kollaboration nach: Am Dienstag veröffentlichten sie eine zweite Aufnahme, die auf Daten der gleichen Messrunde beruht. Sie zeigt ein Objekt namens 3C279. Es ist rund hundertmal weiter entfernt als die Galaxie M87, in der das erste Schwarze Loch fotografiert wurde - aber auch um ein Vielfaches heller. Es handelt sich dabei um einen Quasar: Eine Galaxie, in deren Zentrum sich ein Schwarzes Loch mit etwa einer Milliarde Sonnenmassen befindet. Und das, während es sich eifrig Materie einverleibt, enorm starke Radiostrahlung aussendet.
April 7, 2020, "Vermeintlich schneller als das Licht", Tagesspiegel, by Otto Wöhrbach (including quotes of J.Y. Kim, E. Ros, and J.A. Zensus)
April 8, 2020, "Kosmische Fontänen", Die Welt, by Norbert Lossau (including quotes of J.Y. Kim)
April 08, 2020, "Faszinierende Aufnahme: Schwarzes Loch schleudert Plasmastrahl ins All", Futurezone.at
Forschern gelangen Bilder von sogenannten Jets in einem Schwarzen Loch.
Italian
April 7, 2020, "Dopo quella del buco nero arriva la prima immagine di un getto relativistico", Agenzia Italiana
La tecnica utilizzata da EHT, chiamata interferometria a base molto lunga (VLBI), ha permesso agli scienziati di studiare la morfologia su scala fine del getto vicino alla sua base, dove si pensa abbia origine un'emissione di raggi gamma molto variabile.
April 7, 2020, "Fotografato uno dei fenomeni più potenti del cosmo", Sky tg24
Lo scatto, ottenuto con un livello di dettaglio inedito, ha immortalato per la prima volta un getto di plasma emesso da un buco nero supermassiccio al centro di una galassia, 3C 279, situata nella costellazione della Vergine.
Spanish
April 7, 2020, "Captan la imagen de un chorro de materia emergiendo de un agujero negro", Agencia Efe (including quote from J.Y. Kim)
Un chorro de materia a alta velocidad emergiendo de un agujero negro supemasivo es la nueva imagen captada por el Telescopio Event Horizont (EHT), el mismo que hace un año dio a conocer la primera fotografía de un agujero negro.
La observación proporcionó al equipo internacional de investigadores, entre ellos españoles, alguna sorpresa sobre la forma de ese tipo de chorros y que se recoge en un estudio que publica Astronomy & Atrophysics.
April 7, 2020, "Algo está al acecho en el corazón del cuásar 3C 279", EuropaPress Ciencia (including quote of J.Y. Kim)
La colaboración EHT (Event Horizon Telescope), que publicó la primera imagen de un agujero negro hace un año, ha revelado en el distante cuásar 3C279 los mejores detalles vistos hasta ahora en un chorro producido por un agujero negro supermasivo.
French
April 9, 2020, "Un an après le trou noir M87*, l'EHT livre l'image d'un jet de quasar", Futura News, by Laurent Sacco
Un après l'obtention de la première image d'un trou noir, les membres de la collaboration Event Horizon Telescope (EHT) révèle celles d'un jet associé à un quasar. La résolution obtenue bat un record et montre des détails inédits.
Hungarian
April 8, 2020, "A fekete lyuk árnyéka után egy kvazár plazmanyalábját bontotta fel az Eseményhorizont Teleszkóp", by Krisztina Gabanyi (MPIfR alumna)
Tavaly áprilisban ismerhette meg a világ az első szupernagy tömegű fekete lyukról készített képet, most pedig egy másik különleges égi forrásnak az Event Horizon Telescope (EHT) méréseiből készült rádiótérképében gyönyörködhetünk. 2017 áprilisában ugyanis nem csak az M87 jelű galaxis középpontjában található fekete lyukat figyelték meg ezzel a rádióantenna-hálózattal, hanem a 3C 279 jelű kvazárt is.
Located the site of emission of high-energy gamma rays in the blazar TXS 2013+370
17 February 2020
An international team of astronomers led by the doctoral researcher Efthalia Traianou from the MPI für Radioastronomie has identified the location of the gamma-ray emission in the blazar jet TXS 2013+370. The published results report very-long-interferometry observations of the blazar in the period 2002-13 at four wavelengths up to the challenging 3.5 mm addressed by the Global mm-VLBI Array (GMVA). The images revealed the existence of a spatially bent jet, described by co-existing moving emission features and stationary features. New jet features, lare observed to emerge from the core, accompanied by flaring activity in radio/mm- bands and γ-rays. The work infers that the high energy emission is produced at a distance of the order of about 3 lt-year from the jet apex, suggesting that the seed photon fields for the external Compton mechanism originate either in the dusty torus or in the broad-line region. These results are published in the present issue of the Astronomy & Astrophysics journal, see the original work here.
A wobbling jet with a two-year period
12 February 2020
The quasar PG 1553+113 is the first one showing an approximately two-year quasi-periodic pattern in its γ-ray light curve, which is also revealed at optical frequencies. A study by an international team of radio astronomers led by the MPIfR scientist Rocco Lico has analysed very-long-baseline interferometry observations of the source with a two-month cadence at three bands. The study shows a core-dominated source with a limb-brightened jet structure whose position angle varies in time in the range of 40° to 60°. The core region polarisation percentage varies in the range of a few percent, and the polarisation angle varies from being roughly parallel to roughly transverse to the jet axis. Although the jet wobbling motion indicates that geometrical effects can produce an enhanced emission through Doppler boosting modulation, additional mechanisms are required in order to account for the quasi-periodic variability patterns observed in γ-rays. Further details of this work are presented in the original publication at Astronomy & Astrophysics, see here.
Effelsberg observes methanol emission in nearby galaxies
17 January 2020
A team of astronomers led by the MPIfR PhD candidate Pedro Kumire has observed 36 GHz emission of methanol (CH3OH) in nearby galaxies using the Effelsbeg 100-m radio telescope. Emission was detected in Maffei 2 (at a distance of 19.6 million lt-yr) and IC 342 (at 11.4 million lt-yr) at 36 GHz (4−1 → 30 E transition), but not at 44 GHz transition. Upper limits were reported for M 82, NGC 4388, NGC 5278, and Arp 220. These results are published in Astronomy and Astrophysics, for more detail, check here.
The neutrino detection in the blazar TXS 0506+056, linked to superluminal expansion and limb brigthening in the sub-parsec scale of the source
2 January 2020
The first letter of the Astronomy & Astrophysical journal in the 2020s, led by Eduardo Ros of the MPIfR, reports on the rapid expansion of the centre of the blazar TXS 0506+056, based on millimetre VLBI observations performe with the VLBA. During the months after the neutrino event associated with this source, the overall flux density was showing a steady increase, happening solely within the core. Notably, the core expands in size with apparent superluminal velocity during these six months so that the brightness temperature drops by a factor of three despite the strong flux density increase. The radio jet of TXS 0506+056 shows strong signs of deceleration and/or a spine-sheath structure in the innermost region. This structure is consistent with theoretical models that attribute the neutrino and gamma-ray production to interactions of electrons and protons in the highly relativistic jet spine with external photons originating from a slower moving jet region. Proton loading due to jet-star interactions in the inner host galaxy is suggested as the possible cause of deceleration. Further details can be found in the original publication here.
The first image of a black hole, scientific highlight of 2019 and even of the 2010s
2 January 2020
The announcement and publication of the first image of a black hole in April 2019, with substantial contribution of the MPIfR and its Radio Astronomy/VLBI department, has been highlighted by different media as one of the major scientific discoveries of the last year and of the 2010s. Here we provide some of the links reporting this fact.
Business Insider, 18 November 2019: The most mind-boggling scientific discoveries of 2019 include the first image of a black hole, a giant squid sighting, and an exoplanet with water vapor
The unprecedented photo shows the supermassive black hole at the center of the Messier 87 galaxy, which is about 54 million light-years away from Earth. The black hole’s mass is equivalent to 6.5 billion suns.
Though the image is somewhat fuzzy, it showed that, as predicted, black holes look like dark spheres surrounded by a glowing ring of light.
Scientists struggled for decades to capture a black hole on camera, since black holes distort space-time, ensuring that nothing can break free of their gravitational pull — even light. That’s why the image shows a unique shadow in the form of a perfect circle at the center.
BR 31 December 2019 (in German): Space Highlights 2019 - The Sensation of the Year: first Image of a Black Hole (Weltraum-Rückblick 2019 - Die Sensation des Jahres: erste Aufnahme eines Schwarzen Lochs)
2019 hatte für Astronomie-Fans einiges zu bieten: Den weltweiten Run zum Mond, das erste Foto eines Schwarzen Lochs und gegen Jahresende den Merkurtransit. Gehen Sie mit uns auf die Reise zu den magischen Momenten im Weltall!
wissenschaft.de, 19 December 2019 (in German): Top highlight of the year: the first picture of a black hole (Top-Highlight des Jahres: Das Foto eines Schwarzen Lochs), by Nadja Podbregar
Jedes Jahr kürt das Fachmagazin „Science“ die zehn Highlights des Jahres – und lässt so das wissenschaftliche Jahr noch einmal Revue passieren. 2019 hat die Jury das erste Foto eines Schwarzen Lochs an die Spitze gesetzt – einen astronomischen Meilenstein, der lange als unmöglich galt. Das Bild macht erstmals den dunklen Schatten des Schwarzen Lochs, umgeben von einem hellen Lichtring ausglühenden Gasen, sichtbar. Ebenfalls unter den Highlights des Jahres sehen die „Science“-Editoren unter anderem die erste Gesichtsrekonstruktion eines Denisova-Menschen, einen Quantencomputer, der den weltbesten Supercomputer geschlagen hat und eine wirksame Therapie gegen Ebola.
ORF.at, 30 December 2019 (in German): The Astro-Higholights of the Year - Moon Missions, Planet Hunter, and the first "real" Picture of a Black Hole (Die Astrohighlights des Jahres - Mondmissionen, Planetenjäger und das erste „echte“ Bild eines Schwarzen Lochs) by Annelise Haika and Stefan Walinger
Das spektakulärste Bild des Jahres bot den ersten direkten visuellen Nachweis für ein supermassereiches Schwarzes Loch. Die Messungen dazu wurden bereits 2017 mit einem erdumspannenden Netzwerk aus acht Radioteleskopen gemacht. Es dauerte zwei Jahre, die enormen Datenmengen dieses „Ereignishorizontteleskops“ auszuwerten.
RTBF, 31 December 2019 (French): Picture of the Black Hole, Homo Luzonensis... 7 Scientific Discoveries which marked 2019 (Photo du trou noir, l'homo luzonensis... 7 découvertes scientifiques qui ont marqué 2019)
L’année 2019 a été riche en découvertes scientifiques, découvrez-en une sélection de notre rédaction.
Première photo du trou noir
En avril, des astronomes du monde entier, réunis sous le projet Event Horizon Telescope, ont présenté au monde la première image d’un trou noir lors de six conférences simultanées. Il s'agit du trou noir au centre de la galaxie M87 à 55 millions d'années-lumière de la Terre.
Le Figaro, 25 December 2019 (in French): Black Hole, Homeopathy... The five events which marked science in 2019. Le Figaro delivers its selection of the key moments of science this year, and the ones expeced for 2020. (Trou noir, homéopathie... Les cinq événements qui ont marqué la science en 2019. Le Figaro livre sa sélection des moments-clés de la science cette année... et ceux qui sont les plus attendus pour 2020)
Portrait d’un trou noir
C’est sans conteste la plus grande prouesse scientifique de l’année, et tout simplement la première fois que l’on a pu «voir» un trou noir «pour de vrai».
Pour réaliser ce cliché stupéfiant dévoilé en avril, il aura fallu que tous les plus grands radiotélescopes du monde entier se coordonnent et pointent en même temps vers le trou noir central supermassif niché au cœur de la galaxie elliptique supergéante M87. On distingue ainsi l’ombre de cet ogre, au centre de l’image, qui se détache sur un fond lumineux constitué de gaz et de poussières s’apprêtant à s’effondrer dans sa gueule béante. Magique.
ABC, 19 December 2019 (in Spanish): The black hole in M 87, a historical image (El agujero negro en M 87, una imagen para la historia), invited article by A. Alberdi (MPIfR alumnus) & J.L. Gómez
La revista Science ha seleccionado la primera imagen de un agujero negro como el hito científico más relevante del año. Los investigadores Antxon Alberdi y José Luis Gómez, que participaron en su obtención, hablan sobre su importancia
El Periódico, 28 December 2019 (in Spanish): Black Hole, Time Travel, and Climate Clocks: that was the most-read science this year in our newspaper (Agujeros negros, viajes en el tiempo y despertadores climáticos: esta ha sido la ciencia más leída del año), by Valentina Raffio
La primera imagen de un agujero negro destaca como uno de los avances más destacados del 2019
SINC Agency, 19 December 2019 (in Spanish): The ten scientific achievements in 2019 (Los diez avances científicos de 2019)
La revista Science ha seleccionado los diez avances científicos más importantes de este año. En las primeras posiciones, la fotografía del agujero negro, el rostro de los denisovanos y la explicación de la desaparición de los dinosaurios. Además, la publicación señala tres grandes tareas pendientes de la ciencia.
Vietnam News, 26 December 2019: Top 10 world events of 2019 voted by Vietnam News Agency: First ever black hole image released
It was captured by a global network of eight telescopes, from Hawaii (the US) and Atacama (Chile) to the South Pole and Europe. The historic discovery is said to confirm Albert Einstein’s theory of general relativity.
MEAWW, 25 December 2019: First-ever image of a black hole that stunned the world is Science’s 2019 Breakthrough of the Year, by Mihika Basu
In April 2019, the world saw the first-ever image of a black hole. That’s when an international team of astronomers released a startling close-up image of a black hole’s “shadow,” showing a dark heart surrounded by a ring of light created by photons zipping around it.
Now honoring this feat that was once considered impossible, Science journal has named the Event Horizon Telescope or EHT’s image of a supermassive black hole as its 2019 Breakthrough of the Year.
Predicting Cherenkov telescope detections from Active Galactic Nuclei
14 October 2019
The MPIfR astronomer Roberto Angioni publishes today at the journal Astroparticle Physics a study of the detection prospects for the Cherenkov Telescope Array (CTA). By simulating observations of forty-one γ-ray radio galaxies, extrapolating their Fermi-LAT spectrum into the TeV energy range assuming different spectral shapes, the author predicts that the CTA will detect eleven new TeV radio galaxies with an observational campaign of fifty hours per source. This would increase the sample of very-high-energy radio galaxies by a factor of three. More details, in the original publication here.
Gamma-ray emission at 140 light years from the jet base in the quasar 3C 279
23 September 2019
An international team of astronomers, led by Víctor M. Patiño-Álvarez, affiliated to the MPI für Radioastronomie and now leader of a partner research group at the Mexican Instituto Nacional de Astrofísica Óptica y Electrónica in Puebla has presented a study of the radio-gamma connection in the quasar 3C 279. A comparison of the flux variability in jet features with the gamma-ray variability suggests that the gamma-ray variability is correlated with a particular region downstream from the observed base of the jet at a distance of about 140 lt-yr. This feature shows an apparent superluminal velocity of about 3.7 times the speed of light, implying that one of the gamma-ray emission zones is not stationary. Further details can be found in the original publication at the Astronomy & Astrophysics journal here.
Event Horizon Telescope Collaboration Announces New Management Team
17 September 2019
Professor Anton Zensus, the Chairman of the Board of the Event Horizon Telescope Collaboration, announces the search for a new EHT director and changes to the EHT management, which become effective on September 17, 2019.
The US National Science Foundation has announced the funding of a $12.7M Mid-Scale research innovation grant (MSRI), to develop technologies and techniques that will help to create transformational capabilities for a next-generation Event Horizon Telescope array, envisaged for the second half of the 2020s. Shep Doeleman is PI of this award, and several other US institutions are participating.
“The development of long-term technologies and techniques is an important step towards taking the Event Horizon Telescope into the future. There are none more qualified to lead such a visionary effort than Shep, and we are looking forward to working with him over the coming months to help coordinate the MSRI activities with related work across the EHT collaboration” notes Anton Zensus.
The EHT Board recognizes Shep Doeleman as the Founding Director of the Event Horizon Telescope, acknowledging his leadership to the phenomenal success of the EHT, which led to the first image of a black hole in the galaxy Messier 87.
"The spectacular M87 EHT results have surpassed our wildest expectations, and I am deeply proud of what we achieved as a team. Now the question one hears the most is "what's next?", and the next-generation EHT initiative is the exciting clear response. I look forward to continuing to support the EHT, and am delighted to focus on this new direction." says Shep Doeleman, EHT Founding Director.
The Board will immediately initiate the search to fill the now vacant position of EHT Director, while supporting continuity of the activities of the project through a series of management changes.
* Mike Hecht, Associate Director at Haystack Observatory, will serve as Deputy Project Director;
* Geoff Bower of the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), the vice Chair of the EHT Science Council, will serve as Project Scientist.
* Remo Tilanus of Leiden Observatory will serve as Operations Manager.
* David James of the Harvard-Smithsonian Center for Astrophysics will continue to provide project management support to the Team.
“The EHT Management Team is enhanced to address the evolving management and communication needs of our collaboration, which has seen rapid growth in membership, and increasing complexity in operations, scientific and development activities. Shep has graciously offered to continue to advise the Management Team during the transition period” adds Zensus.
Further information:
Prof. Dr. J. Anton Zensus |
Dr. Colin J. Lonsdale |
Prof. Dr. Eduardo Ros |
EHT Board Chairman |
EHT Board Vice-Chairman |
EHT Board Executive Secretary |
MPI für Radioastronomie, Bonn, Germany |
MIT Haystack Observatory, Westford, MA, USA |
MPI für Radioastronomie, Bonn, Germany |
Tel. +49 228 525 378 |
Tel. +1 617 715 5575 |
Tel. +49 228 525 125 |
A Test of General Relativity at The Galactic Center
25 July 2019
In a detailed study of a star orbiting the supermassive black hole at the center of our Galaxy, researchers report that Einstein’s theory of general relativity (GR) accurately describes motion around this massive structure. Tuan Do, Andrea Ghez and their colleagues including Gunther Witzel from the Max Planck Institute for Radio Astronomy in Bonn, Germany, report novel spectral data and expanded analyses. The findings are presented in this week’s issue of the magazine „Science“ (UCLA Press Release, 25 July 2019). [more]
Gamma-ray emission in radio galaxies under the VLBI scope
15 July 2019
The POLAMI Collaboration has published a study, led by the MPI für Radioastronomie researcher R. Angioni, of the gamma-ray emission of Southern radio galaxies. These results are published in the last issue of the Astronomy & Astronomy journal. The study shows that the brightness of the core of the radio sources correlates with the gamma-ray emission, as seen in blazars. However, the gamma-ray luminosity does not show dependence with the compact radio emission of the core of the galaxies, which is a common indicator of Doppler boosting. The authors conclude that the gamma-ray emission in radio galaxies is not driven by orientation-dependent effects, as in blazars, according with the unified model of jetted active galactic nuclei. More information is available here.
The large gamma-ray flare of the flat-spectrum radio quasar PKS 0346−27
12 July 2019
A multi-messenger study led by R. Angioni of the MPI für Radioastronomie, published in the present issue of Astronomy & Astrophysics, reports on the long- and short-term flux and spectral variability from the radio quasar PKS 0346−27, producing gamma-ray light curves with different time binning. Evidence of short-time scale variability down to 90 min is presented. The source shows remarkable properties during an outburst in May 2018, and is a promising target for future ground-based Cherenkov observatories. More information is available at the original publication here.
The gamma-loud radio galaxy 3C 264
4 July 2019
A team of astronomers led by the astronomer B. Boccardi of the MPI für Radioastronomie publishes in the latest issue of Astronomy & Astrophysics a high-resolution radio study of the gamma-ray emitting galaxy 3C 84. The authors present a adio and X-ray analysis of the jet in 3C 264. They determine the main physical parameters of the parsec-scale flow and explore the implications of the inferred kinematic structure for radiative models of this γ-ray emitting jet. The publication suggests that the high-energy emitting region is located at the end of the acceleration zone of the jet, either in the jet layer or in the spine. Further information can be found here.
A study of the physics of the complex jet in the blazar S5 0836+710
3 July 2019
The last issue of the journal Astronomy & Astrophysics reports the results of a thorough analysis of the jet profile of the high-resolution images of the blazar S5 0836+710. The study is led by the MPI für Radioastronomie researcher L. Vega García. The authors ran numerical calculations of stability of a relativistic, sheared jet over a range of different jet parameters, based on the assumption that the observed structures are generated by growing Kelvin–Helmholtz instability modes. The results yield physical parameters of the jet, with a Lorentz factor of 12 and an internal Mach number of 12, as well as a jet-to-ambient medium density of 1/1000. More details can be found in the original publication here.
Media coverage (selection): Astronomers capture the first image of a black hole
Printed media
English:
April 10, 2019: "Darkness Visible, Finally: Astronomers Capture First Ever Image of a Black Hole", NYT Dennis Overbye
Astronomers at last have captured a picture of one of the most secretive entities in the cosmos.
April 10, 2019: First-ever picture of a black hole unveiled, National Geographic, by Nadia Drake
Using a telescope the size of the planet, astronomers have captured the first image of this space oddity. Here's why that matters.
April 10, 2019: Scientists Unveil First Black Hole Image, Sky & Telescope, by Camille M. Carlisle
The Event Horizon Telescope collaboration has reconstructed the shadow of a supermassive black hole.
April 10, 2019: Astronomers Capture First-Ever Image of a Supermassive Black Hole, Smithsonian Magazine, Jay Bennet
April 10, 2019: How the Event Horizon Telescope imaged an invisible black hole, Astronomy, by Erika K. Carlson
Hint: it's much harder than it sounds.
German:
May 14, 2019: Das erste Foto eines Schwarzen Lochs, Spektrum der Wissenschaft, S. Britzen & A. Müller
Endlich! Das schon seit Jahren erwartete, erste direkte Bild eines Schwarzes Lochs ist nun mit einem globalen Netzwerk aus Radioteleskopen gelungen. Das spektakuläre »Foto« gibt den Blick frei in das Herz der Galaxie Messier 87 in 55 Millionen Lichtjahren Entfernung. Dort sitzt eines der größten bekannten Schwarzen Löcher, das Materie verschlingt, diese zum Leuchten bringt und so das Loch sichtbar werden lässt.
April 21, 2019: Ein Fleck, hinter dem sich ein Stück Ewigkeit verbirgt, Süddeutsche Zeitung, comment by Marlene Weiß
Das Foto vom Schwarzen Loch wird wohl nie einen praktischen Nutzen haben. Doch es zeigt, dass der Mensch die Grenzen seiner Vorstellungskraft überschreiten kann. In Zeiten, in denen der Homo sapiens seinen Planeten zugrunde richtet, ist dies von besonderer Bedeutung.
April 19, 2019: Jenseits der Grenze, Süddeutsche Zeitung, Comment by Marlene Weiß
Die Bilder vom Schwarzen Loch sind faszinierend. Sie zeigen, dass Menschen etwas sichtbar machen können, das ihre Welt überschreitet. Was bedeutet das?
April 17, 2019: Entdeckersehnsucht, FAZ, Comment by Sibylle Anderl (IMPRS alumna)
Hinter großen wissenschaftlichen Durchbrüchen stehen heute meist Hunderte von Forschern. Dass unsere Sehnsucht nach einem entscheidenden Einzelentdecker dennoch groß ist, konnte man jüngst erneut beobachten.
April 15, 2019: Ein historischer Schatten, FAZ, Sibylle Anderl (IMPRS alumna)
Schwarze Löcher galten lange als Inbegriff des Unbeobachtbaren. Bevor nun dem EHT erstmalig eine direkte Abbildung gelangt, stellte sich lange die Frage nach ihrer Existenz.
April 13, 2019: Zwei Jahre bis zum Bild, FAZ, Sibylle Anderl (IMPRS alumna), including quotes of J. Anton Zensus
Die Beobachtung mit dem „Event Horizon Telescope“ ist ein internationaler Erfolg. Zum ersten Mal konnten Wissenschaftler ein Schwarzes Loch direkt visuell nachweisen. Doch der Schnappschuss wurde lange Zeit im Voraus geplant.
April 12, 2019: Was uns schwarze Löcher über die Geheimnisse des Universums verraten, Der Spiegel, Johannes Grolle (includes interviews with J. Anton Zensus and Thomas P. Krichbaum)
April 11, 2019: Annäherung ans Schwarze Loch, Süddeutsche Zeitung, Marlene Weiß and Patrick Illinger
Was passiert, wenn man in ein Schwarzes Loch hineinfällt? Und sehen die Massemonster wirklich so aus, wie auf der nun vorgestellten Aufnahme? Antworten auf die wichtigsten Fragen.
April 11, 2019: „Wie der Eingang zur Hölle“, Der Tagesspiegel, by Ralf Nester, quoting J. Anton Zensus
April 11, 2019: "Wissenschaftlicher Durchbruch: Schwarzes Loch M87: Was auf dem Sensationsfoto zu sehen ist", Focus, Martin Odenwald (including quotes of J. Anton Zensus)
April 11, 2019: Sinnvoller als bemannte Missionen zum Mond, Süddeutsche Zeitung, Comment by Marlene Weiß
Das erste Foto eines Schwarzen Lochs zeigt eine Welt, in der Zeit und Raum ihre Bedeutung verlieren. Das ist nicht nur faszinierend, es bringt auch wichtige wissenschaftliche Erkenntnisse.
April 10, 2019: So sieht ein Schwarzes Loch wirklich aus, Die Zeit, Alina Schadwinkel (including quotes of Eduardo Ros)
April 10, 2019: "Schatten eines Giganten", FAZ, comment by Sibylle Anderl (IMPRS alumna)
Das Event Horizon Telescope hat das erste Bild eines Schwarzen Lochs veröffentlicht. Die Beobachtung ist nicht nur wissenschaftlich wegweisend. Sie zeigt auch, dass sich die europäischen Astronomen nicht verstecken müssen.
April 10, 2019: Und es ward Licht, Spiegel Online, by Markus Becker (including quotes by Michael Kramer and Eduardo Ros)
April 10, 2019: Das erste Bild eines Schwarzen Lochs, FAZ, by Sibylle Anderl (IMPRS alumna)
Dem Event Horizon Telescope ist die erste Aufnahme des „Schattens“ eines Schwarzen Lochs gelungen. Das abgebildete Objekt im Zentrum der Galaxie M87 entspricht in verblüffendem Maß den Erwartungen.
April 10, 2019: Erstes Bild von Schwarzem Loch, Die Welt (including quotes by J. Anton Zensus)
Bislang gab es von Schwarzen Löchern nur Illustrationen. Jetzt haben Astronomen das erste Bild gemacht - und sprechen von einer «unglaublichen Errungenschaft». Acht Observatorien waren für die Aufnahme notwendig.
April 10, 2019: Wissenschaftler fotografieren erstmals ein schwarzes Loch, golem.de, by Werner Pluta
Die Existenz von schwarzen Löchern war schon seit Langem vorhergesagt, bisher konnten sie aber nur indirekt nachgewiesen werden. Dem Projekt EHT ist es gelungen, mit Hilfe eines virtuellen, erdumspannenden Teleskops erstmals ein Bild eines schwarzen Lochs aufzunehmen.
April 10, 2019: Das Monster zeigt seine Zähne, Spektrum der Wissenschaft, by Robert Gast (with references to Thomas P. Krichbaum and J. Anton Zensus)
April 10, 2019: Forscher zeigen erstmals Foto von einem schwarzen Loch, Spiegel Online, by Christoph Seidler
Ein weltweites Netzwerk von Teleskopen hat eine Beobachtung ermöglicht, auf die Astronomen seit Jahrzehnten warten: Das erste Bild von einem schwarzen Loch. Wir erklären, was zu sehen ist.
April 10, 2019: Ein Foto, das eigentlich unmöglich ist, Der Tagesspiegel, by Ralf Nestler
French:
April 13, 2019: Première image d'un trou noir supermassif : des commentaires d'Aurélien Barrau, Futura Sciences, by Laurent Sacco
On l'attendait depuis un moment et cet évènement fera date dans l'histoire de l'exploration du Cosmos par l'Humanité. La première image d'un trou noir prise avec l'Event Horizon Telescope a été dévoilée et c'est celle du trou noir supermassif au cœur de la galaxie M87. Une nouvelle fenêtre sur la gravitation quantique s'ouvre peut-être, selon Aurélien Barrau.
April 10, 2019: Ce que révèle la première photo d'un trou noir, 7sur7 (including quote by J. Anton Zensus)
Spanish:
Radio, television, internet movies, and podcasts
English:
April 23, 2019: How to make an image of a black hole, Deutsche Welle, Social Media, short video featuring Helge Rottmann, Jan Wagner, and Eduardo Ros
April 10, 2019: Discovering the black hole: Why does it matter?, Interview to J. Anton Zensus, News China TV
German:
French:
April 13, 2019: "Ses équations sont toujours conformes aux détections" : comment la première image d'un trou noir révèle tout le génie d'Albert Einstein, France TV Info, quoting Eduardo Ros
La publication d'une image de trou noir était encore inimaginable il y a quelques années. De nombreux chercheurs du projet Event Horizon Telescope ont salué leur père spirituel, un certain Albert Einstein, dont les travaux sont toujours d'actualité.
Spanish:
Twin, but asymmetric jets in the radio galaxy NGC 1052
26 February 2019
A study of twenty-nine observations using very-long-baseline interferometry in the radio galaxy NGC 1052, led by the MPIfR PhD student Anne-Kathrin Baczko, has revealed new details of the nature of the twin jet in this object. Interestingly, the approaching (eastern) jet has higher kinetic energy, whereas the receding (western) jet has a larger internal energy or magnetic flux. The inner structure of the jet can be explained by a spine-sheath with a fast inner layer and a slower outer layer. These results are published in the present issue of the Astronomy & Astrophysics journal, for the original publication, see here.
Resolving the innermost region of the radio galaxy NGC 1275 with mm-VLBI
19 February 2019
Using the Global mm-VLBI Array, an international team of astronomers led by J.Y. Kim from the MPI für Radioastronomie, has analysed the inner polarised structure of the nearby radio galaxy 3C 84 (NGC 1257), reaching resolutions of 50 μas (corresponding to ∼200 schwarzschild radii). The results suggest that the emission is associated with an underlying limb-brightened jet. The images match in resolution the ones obtained with space VLBI in our group, several months ago (see below). These results are published in the present issue of the journal Astronomy & Astrophysics, for the original publication, see here.
Helical magnetic fields and a recollimation shock in the classical quasar CTA 102
12 February 2019
The popular radio source CTA 102 (see the song by the Californian band The Byrds from 1967) continues being the object of study of radio astronomers. A new publication apppeared today, led by the MPIfR astronomer Carolina Casadio, reports on the magnetic field configuration and the interaction between traveling shocks and a recollimation shock in its relativistic jet. The study is based on observations at the wavelengths of 3.5 mm and 7 mm performed in the mid 2010s. A Faraday rotation analysis shows a gradient in the jet and intrinsic electric vector position angles oriented around the centroid of the innermost jet feature (core), suggesting the presence of large-scale helical magnetic fields. Monitoring shows a feature moving superluminally and crossing the core (central, brightest) region. The polarisation orientation is different when the mentioned feature is exiting the core or crossing a stationary feature. The interaction between the superluminal component and a recollimation shock could have triggered the multi-wavelength flares. The variability Doppler factor associated with such an interaction is large enough to explain the high-energy emission and the remarkable optical flare occurred very close in time. Further details on this work can be found at the original publication, see here.
New Global Millimetre VLBI Array Survey released
01 February 2021
The new survey of the GMVA, led by Dhanya G. Nair at the MPI für Radioastronomie, has been released, simultaneously to the corresponding publication at the present issue of the Astronomy & Astrophysics journal. The survey target source list has been compiled from the MOJAVE (Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments) sample, using the following selection criteria:
a) | 15 GHz correlated flux density, Sc ≥ 0.5 Jy on baselines of ≥ 400 Mλ; | |
b) | compactness at longest spacings, Sc /SVLBA ≥ 0.4 where S VLBA is the 15 GHz total clean flux density; | |
c) | declination δ ≥ 15°. |
With these selection criteria, a total of 162 unique sources have been selected, comprising 89 quasars, 26 BL Lac objects, 22 radio galaxies and 25 unidentified sources. For further details, please visit the dedicated webpage. Images can be downloaded here.
Helical magnetic fields in the bent jet of the quasar OJ 287
November 12, 2018
Deep in the heart of M 87
September 12, 2018
A new publication led by MPIfR astronomers (see here) presents Global mm-VLBI Array (GMVA) observations at 3.5 mm wavelength of the nearby radio galaxy Messier 87, the central galaxy of the Virgo cluster in a distance of about 50 million light years. The highlight image shows the central region of M 87 at an angular resolution of ~50 μas (7 Schwarzschild radii).
The imaging reveals a parabolically expanding limb-brightened jet which emanates from a resolved VLBI core of about ten Schwarzschild radii in size. The observed brightness and compactness of the central feature suggests magnetic energy dominance at the jet base. Data yield an estimate the diameter of the jet at its base to be about five Schwarzschild radii assuming a self-similar jet structure. This suggests that the sheath of the jet may be anchored in the very inner portion of the accretion disk. Combined images reveal faint emission at the center of the edge-brightened jet on scales smaller than light years.
Charge in the hole
August 12, 2018
Black holes have mass, angular momentum and potentially a charge. While the first two were measured routinely for some time now, constraining a black hole’s charge is more difficult. A comment by Marios Karouzos in "Nature Astronomy" refers to an original paper by MPIfR authors led by Michal Zajaček in MNRAS, proposing an observational way to test limits on the charge of Sgr A*, the black hole at the centre of the Milky Way. The original publication is available here.
Extreme outflows in radio-loud narrow-line Seyfert 1 galaxies
April 17, 2018
A team of astronomers led by Stefanie Komossa from the MPI für Radioastronomie in Bonn has studied four narrow-line Seyfert 1 galaxies and discovered extremely shifted spectral lines in their spectra, which indicate gas flying away from the central regions at speeds as high as 2450 km/s. These galaxies are also emitteres in the radio part of the electromagnetic spectrum. These results suggest that those galaxies are relatively young (in astronomical terms) with lifetimes of the order of magnitude of a million year. The results are published in the present issue of the journal Monthly Notices of the Royal Astronomical Society, to be found here.
New images from the Southern radio sky
February 7, 2018
An international team of astronomers led by C. Müller (Radboud U. & MPI für Radioastronomie) has published new images from a sample of southern blazars in the framework of the TANAMI program. These results are presented in the actual issue of Astronomy & Astrophysics. A powerful array of Southern telescopes located in Australia, Antarctica, Chile, New Zealand, and South Africa was assembled to obtain these unprecedented images. The TANAMI team found that that γ-ray loud sources tend to be more compact on parsec-scales and have higher brightness density in their central regions than γ-ray quiet sources. More information can be found in the original publication here.
Synthetic images from remote galaxies: understanding obscured emission
January 12, 2018
Numerical simulations performed by a team of astronomers in Frankfurt, Bonn, and Valencia led by C.M. Fromm have managed to synthesize the emission from radio objects with an obscuring torus. The numerical code Ratpenat was used to model several jets embedded in various ambient medium and torus configurations and subsequently computed their images, including jet emission and torus absorption. These simulations help understanding the physics of jets and tori, and suggets observational methods such as the core-shift to discern between different physical scenarios in the jet (e.g., if they have equal pressure inside and outside the jet, or if the pressure outside is larger). These results are shown in the present issue of the journal Astronomy & Astrophysics, for more details see here.
And it burns, burns, burns... the ring of fire and orphan gamma-ray flares
20 November 2017
A team of radio astronomers led by Nicholas MacDonald, affiliated to the MPI für Radioastronomie and Boston University, has developed the ring of fire model to explain the origin of γ-ray flares in blazars without correspondence in the radio band. A ring of shocked plasma along the relativistic outflows in blazars can explain the missing emission in the radio observed in a sample of blazars, the most prominent sources in the non-thermal sky (that is, with radiation of non-thermal origin, both in the radio and the γ bands. Further details of this work, connecting theory and observations, can be obtained in the original publication in the Astrophysical Journal here.
Blazar 3C 273 probed at the highest resolution with space-VLBI
22 August 2017
The RadioAstron space mission continues providing sharp images from the most compact objects in the radio sky. Observations led by Gabriele Bruni at the MPI für Radioastronomie of the radio source 3C 273 in the framework of the Polarisation Key Science Projet of RadioAstron are reported in the present issue of the journal Astronomy & Astrophysics. The results reveal that the nuclear brightness temperature of thte source is hundred times larger than the exceptional value detected in earlier observations in 2013. New features are also present in the jet. Further details can be found at the original publication here.
Measuring the masses of young stars, a puzzle for stellar models
June 12, 2017
An international team of astronomers led by Bonn researcher Rebecca Azulay reports in the present issue of Astronomy and Astrophysics results from astrometric measurements of the pre-main-sequence stars HD 160934 A and C, EK Dra, LO Peg, and PW And. The results present observational evidence that the stellar evolutionary models underpredict the mass of those stars by 10%-40%, challenging the present approach for modeling. The authors suggest that the magnetic activity of stellar coronae triggers gyrosynchrotron emission from non-thermal, accelerated electrons. Detailed information can be found in the original publication here.
Misaligned Active Galactic Nuclei, paving the way to the Cherenkov Telescope Array
May 12, 2017
Radio loud Active Galactic Nuclei (AGN) with the jet not pointing directly to the observer are a new class of GeV emitters revealed by the Fermi-LAT space telescope. A team of astronomers led by the MPIfR PhD researcher Roberto Angioni publishes in the present issue of Astroparticle Physics a study of the impact of the Cherenkov Telescope Array (CTA) on the misaligned AGN class and proposes observational strategies to optimise their detection. More information, directly in the original publication here.
Millimetre Eyes to the Black Hole Universe
March 30, 2017
Cutting-edge observations aim to directly image the immediate environment of a black hole on the first two weeks of April 2017 by two arrays of telescopes including the highly-sensitive Atacama Large Millimetre Array. The „Event Horizon Telescope”(EHT) is an international project which will allow to test Einstein’s Theory of General Relativity in an extreme regime. The Global Millimetre VLBI Array, managed by the Max Planck Institute for Radio Astronomy, will complement these observations. A number of European research institutes participate in the observations, to be partially post-processed at the correlator center in Bonn.
The GMVA network will perform observations with 14 antennas from March 31 to April 4, focusing on several active galaxies, among those 3 targets will be observed jointly with the ALMA telescope in Chile. The 100-m radio telescope in Effelsberg will participate in the GMVA observations. For the EHT observations, see the MPIfR and the MPG press releases here and here, respectively.
The analysis of the GMVA observations including phased ALMA will be completely postprocessed at the MPIfR correlator in Bonn.
Following sources will be observed with joint observations from the GMVA and ALMA: Sgr A* (PI Brinkerink, Radboud Univ. Nijmegen), 3C 273 (PI Akiyama, MIT & National Astronomical Observatory of Japan (NAOJ)), and OJ 287 (PI Gómez, Instituto de Astrofísica de Andalucía). Additionally, GMVA-only observations will be performed from March 30 to April 2, for following sources: M 87 (PI Asada, ASIAA), NGC 1052 (PI Baczko, MPIfR), NGC 1275 (PI Nagai, NAOJ), and gamma-loud blazars (PI Marscher, Boston University). The block schedule for the Spring 2017 session is shown here.
A team of MPIfR astronomers is traveling to the telescopes for supporting and performing the observations, namely, Rebecca Azulay (Pico Veleta), Sven Dornbusch (APEX), Thomas P. Krichbaum (Pico Veleta), Helge Rottmann (Pico Veleta and ALMA), and Alan Roy (APEX). An extended team is traveling for the GMVA observations to the house telescope, the 100-m dish in Effelsberg 40 km away from Bonn, coordinated by Thomas Krichbaum before he leaves to Pico Veleta: Walter Alef, Roberto Angioni, Uwe Bach, Jae-Young Kim, Cornelia Müller (Radboud Univ. Nijmegen), Eduardo Ros, Efthalia Traianou, and Laura Vega García.
Can millimetre-wavelength interferometry observations challenge the existence of black holes?
March 2, 2017
Andrei Lobanov, staff scientist at the MPIfR discuss in the present issue of Nature Astronomy the existence of black holes and an observational test for those, based on the study of the magnetic fields in the central regions of super massive objects. The Event Horizon Telescope has the capability to observe the polarised emission in the neighbourhood of the putative event horizon, and magnetic field values beyond 104 Gauss may challenge the standard interpretation of the physics in these objects. More information in the original publication here.
The origin of the γ-ray emission in the 'wobbling' jet in the blazar OJ 287
January 6, 2017
MPIfR astronomers led by J. Hodgson have identified the location of the high-energy emission in the BL Lac object OJ 287, known by its periodic flux density outbursts and its wobbling parsec-scale jet. These findings are based in the comparison of very detailed images obtained with the Global Millimetre VLBI Array with the γ-ray light curves from the Fermi space telescope. The international team could estimate the strength of the magnetic field, larger than 1.6 Gauss in the central region and below 0.4 Gauss in the relativistic stream. This study has been published in the present issue of the Astronomy & Astrophysics journal, see here.
Data for 2.5 years from the Effelsberg Key Science Project F-GAMMA released
28 November 2016
The present issue of the journal Astronomy & Astrophysics reports the light curves and spectra of a sample of about 60 sources observed with the Radio Telescope Effelsberg (together with the IRAM 30 m telescope at Pico Veleta). This unprecedented data base reveals that all observed gamma-loud radio galaxies are variable accross all frequencies with variability increasing at the higher ones. Interestingly, radio flux at wavelengths of 3.5 mm and 2.0 mm correlate with gamma-ray fluxes. The F-GAMMA project is one of the most relevant radio astronomical projects at present, connecting the radio emission of blazars with their high-energy properties. More information is available at the original publication, led by the MPIfR astronomer L. Fuhrmann, here.
The puzzling Narrow-Line Seyfert Galaxy 1H 0323+342, observed at the highest resolution in the radio regime
1 November 2016
A team of astronomers led by L. Fuhrmann from the MPIfR has observed the radio galaxy 1H 0323+342 with an armada of telescopes including the Effelsberg 100-m and IRAM 30-m telescopes, in the course of the F-GAMMA program. The observations reveal superluminal motions with apparent speeds up to seven times the light speed. Those allowed the international team to estimate the viewing angle of the relativistic flow, to be smaller than 9º. These findings have been published in the present issue of the journal Research in Astronomy and Astrophysics. More information can be found at the original publication here.
The quasar 3C 273 and its γ-ray flares: results from a multi-band campaign
September 27, 2016
Total intensity and polarization observations of the quasar 3C 273 were carried out between 2013 December 28 and 2014 January 03 using the Fermi-Large Area Telescope, Swift-XRT, Swift-UVOT, and Korean VLBI Network telescopes. No relationship was found with the radio total intensity and polarised emission. However, the coincidence of the increase in radio polarization with the X-ray flux supports the picture that X-rays are produced via inverse-Compton scattering of radio photons. Correlation was found between a flare in the optical/near-UV passbands and a concurrent γ-ray flare These results are presented in the last issue of the journal Monthly Notices of the Royal Astronomical Society, see here.