Research Highlights
Here we show recent research results from the Radio Astronomy/Very-Long-Baseline Interferometry department.
Unlocking the Secrets of Quasar Jets, the case of NRAO 530
23 December 2024
A team of scientists led by Misha Lisakov from the Max Planck Institute for Radio Astronomy (MPIfR) has made a remarkable discovery about the powerful magnetic fields and jet dynamics in the quasar NRAO 530. By analyzing quasi-simultaneous multifrequency observations, the researchers have revealed a kilogauss magnetic field strength near the central supermassive black hole, making it one of the strongest reported for active galaxies. The study, which provides unprecedented insights into the accretion disk and magnetic field strength, also includes the first-ever VLBI measurement of Faraday rotation, offering new clues about the particle density and magnetic field strength at the jet's outset. The complex shape of the jet in NRAO 530 is consistent with the expected behavior of a precessing jet, with a period estimated to be around 6 ± 4 years. Read the full paper in Astronomy & Astrophysics to learn more about this research, published in the final version available at the journal webpage here.
Discovering the Persistent Connection Between Millimeter and Gamma-Ray Emissions in PKS 1424−418
13 December 2024
Published in the present issue Astronomy & Astrophysics, this study led by the MPIfR researcher DaeWon Kim reveals a long-term, strong correlation between millimeter (mm) radio and gamma-ray (γ-ray) emissions in the flat-spectrum radio quasar (FSRQ) PKS 1424−418. Using over 8.5 years of data from ALMA and Fermi-LAT, the astronomers team confirmed a unique, persistent link between these emissions with no significant time delay, suggesting a direct connection in the relativistic jet near the quasar's central engine. The study highlights the dynamic opacity of the jet's inner regions and observes spectral changes during γ-ray flares, shedding light on the physical processes driving these high-energy phenomena. For more information, see the original publication here.
The Extremes of AGN Variability and Binary Supermassive Black Holes
1 December 2025
Led by S. Komossa from the MPIfR, this review published at the Serbian Astronomical Journal explores the extremes of emission-line and continuum variability in Active Galactic Nuclei (AGN), providing unique insights into the physics and geometry of their central engines. It highlights the most extreme cases of continuum and optical emission-line variability, discusses the proposed interpretations, and addresses challenges in identifying changing-look (CL) AGN. A call for larger samples of CL narrow-line Seyfert 1 galaxies and CL LINERs at opposite ends of the accretion regime is emphasized. Additionally, the review examines evidence for semi-periodic variability in broad lines and continuum emission, potentially signaling the presence of binary SMBHs. Results from the MOMO project, which densely monitors the binary SMBH candidate OJ 287, are presented, showing that recent findings rule out the leading binary model and demand new modeling based on a primary SMBH mass of hundred million solar masses. Future time-domain surveys and upcoming gravitational wave detections will be pivotal in advancing this exciting frontier in astrophysics. More details can be found at the original publication here.
The Mysterious Jet of Neutrino Candidate PKS 1717+177
21 November 2024
Published in Monthly Notices of the Royal Astronomical Society (December 2024), a new study led by Silke Britzen from the MPIfR investigates the BL Lac object PKS 1717+177, identified as a potential neutrino-emitting active galactic nucleus (AGN) by IceCube's point-source stacking analysis. Through over two decades of high-resolution radio observations and multiwavelength light curve analysis, the authors uncover a striking deflection in the jet at ~0.5 milliarcseconds from the core. This bend evolves into a zig-zag pattern over time, accompanied by periodic brightening at the deviation point. Possible explanations include interaction with a dark massive object, a dense circumnuclear cloud, or gravitational lensing. These findings offer a novel glimpse into jet dynamics and their potential link to neutrino production. For more information, see the original publication here.
Unraveling Jet Dynamics with 3D Hybrid Fluid-Particle Simulations
25 October 2024
The study, published in present issue of Astronomy & Astrophysics, and led by Joana A. Kramer, represents a significant advancement in the modelling of relativistic jets in active galactic nuclei. By integrating synchrotron radiative losses into 3D hybrid fluid-particle simulations, the research team has developed a more comprehensive approach to understanding these complex phenomena. By leveraging the PLUTO code's cutting-edge Lagrangian particle module, the authors have successfully addressed significant limitations in traditional relativistic magnetohydrodynamic (RMHD) simulations, resulting in a more precise representation of non-thermal particle effects. By comparing emission maps to those of the radio galaxy Centaurus A, the authors demonstrate the impact of synchrotron cooling and the value of incorporating non-thermal radiation processes. This work offers a comprehensive insight into jet structure, including edge-brightening and magnetic field configurations, providing a robust foundation for future comparisons with observed polarized jet emissions. For more details, see the original publication here.
A New Era in Radio Astronomy: Direct Imaging from Closure Traces
20 September 2024
Hendrik Müller, a researcher affiliated to the MPIfR, has presented a significant breakthrough in radio interferometry. His innovative method, which leverages closure traces, offers a promising solution to the longstanding challenges associated with gain and leakage corruptions in radio imaging. Unlike traditional methods that rely on complex calibration procedures, Müller's approach allows for direct imaging from closure traces, a type of closure quantity that is inherently independent of gains and leakages. This groundbreaking technique has the potential to revolutionize radio astronomy, especially for projects like the Event Horizon Telescope (EHT), where these corruptions are particularly problematic. Learn more about this research in the original publication here.
Unveiling the Secrets of a High-Redshift Blazar
30 August 2024
A team led by Petra Benke, a researcher at the Max Planck Institute for Radio Astronomy (MPIfR), has presented a groundbreaking study of the flaring blazar TXS 1508+572. By employing VLBI, the researchers have discerned notable morphological alterations, spectral index fluctuations, and superluminal velocities in this remote object. This research offers invaluable insights into the evolution of active galactic nuclei (AGN) jets and provides novel constraints on cosmological models. Further information can be accessed in the original publication here.
Unveiling the Secrets of Sgr A*: A Deep Dive into Relativistic Effects and Near-Infrared Variability
06 August 2024
What's behind the flickering light of the supermassive black hole at the centre of our galaxy, Sgr A*? A team of astronomers led by Sebastiano von Fellenberg from the MPIfR, have taken a new approach to answer this question. They've been looking at the subtle time differences in Sgr A*'s near-infrared changes. By looking at the skewness of the light curve with a third-moment structure function, they were able to identify the rapid rise and decay times in the light's intensity. Their findings suggest that Doppler boosting, rather than gravitational lensing, plays a key role in this cosmic dance. This research not only helps us understand the relativistic effects at play near Sgr A*, but also offers new tools for exploring other astronomical phenomena. More details can be found at the original publication in Astronomy & Astrophysics, released today, here.
First Detection of New Methanol Maser Transitions in Star-Forming Regions
30 July 2024
A team of astronomers led by Pedro Humire from the Max Planck Institute for Radio Astronomy (MPIfR) has made a groundbreaking discovery in the field of star formation. For the first time, they have detected methanol maser emissions in molecular transitions at 181.295 and 326.961 GHz, respectively. Using the APEX 12 m telescope, the team surveyed low-mass Galactic star-forming regions, uncovering these rare emissions in six out of 19 sources. Their findings confirm the maser nature of these transitions in several regions, including CARMA 7 and L1641N, and expand our understanding of methanol masers in low-mass star-forming environments. This discovery opens new avenues for studying the conditions around newly forming stars. Further details are available at the publication released today in Astronomy & Astrophysics here.
Unveiling the X-ray Secrets of 3C 286: A Close Look at an Unusual Radio-Loud NLS1 Galaxy
26 July 2024
A team of astronomers led by Su Yao, Stefanie Komossa, and Alex Kraus from the Max Planck Institute for Radio Astronomy (MPIfR), has conducted the first in-depth X-ray study of the Fermi-detected, steep-spectrum radio source and radio-loud narrow-line Seyfert 1 (NLS1) galaxy, 3C 286. This object is a key calibrator in radio astronomy and has a fascinating blend of characteristics, including a damped Lyα system and γ-ray emission from a misaligned jet. The team's observations with XMM-Newton and Chandra show that the X-ray spectrum is pretty complex. It can't be described by just a simple power law. It also includes a significant soft excess, which is likely due to a blackbody component. They also spotted what might be X-rays coming from outside the nucleus, near the radio lobes. These results give us new insights into how these unique active galactic nuclei (AGN) produce γ-rays and help us understand how AGNs work. The results, presented today in the Monthly Notices of the Royal Astronomical Society, are available in the original publication here.
First ever VLBI detection of the core of the radio galaxy Fornax A
26 June 2024
A team of astronomers led by Georgios Paraschos from the Max Planck Institute for Radio Astronomy (MPIfR) have achieved this breakthrough. This breakthrough lets scientists examine the heart of Fornax A in amazing detail, revealing intense non-thermal emissions from its active nucleus where powerful jets are launched into space. The team's observations confirm the presence of a compact core emitting synchrotron radiation and hint at more extended structures on larger scales. By unveiling these new features, the study provides crucial insights into how jets form and propagate in active galaxies, enhancing our understanding of these dynamic and energetic cosmic phenomena. More details on these results, presented today in the journal Astronomy & Astrophysics, are available in the original publication here.
Evidence for a toroidal magnetic field in the nucleus of 3C 84
27 May 2024
A study in the current issue of the journal Astronomy & Astrophysics explores the relativistic radio jet of the nearby active galactic nucleus (AGN) 3C 84, using 22 GHz very long baseline interferometry (VLBI) to study its sub-parsec region. By analysing the total intensity and linear polarisation of 3C 84, the researchers tested different relativistic magneto-hydrodynamic (RMHD) simulations, adjusting the jet's bulk Lorentz factor and magnetic field configurations (toroidal, poloidal, helical). The results confirm a limb-brightened jet structure with electric vector position angles (EVPAs) aligned with the jet flow in the centre, but orthogonal near the edges. The observed geometry is consistent with a spine-sheath model with mildly relativistic flow and a toroidal magnetic field, bridging the gap between RMHD simulations and VLBI observations. These results are led by MPIfR junior researcher Georgios F. Paraschos; more information is available here.
Around the bend in 3C 345's jet
24 April 2024
The current issue of Astronomy & Astrophysics features a study led by PhD student Jan Röder that examines the flat-spectrum radio quasar 3C 345, known for its γ-ray activity since the mid-2000s. The focus is on the 2009 γ-ray burst associated with a relativistic outflow observed with 43 GHz Very Long Baseline Interferometry (VLBI). By analysing data from the VLBA-BU-BLAZAR and BEAM-ME programmes, as well as new observations at 23, 43 and 86 GHz between 2017 and 2019, the research team aimed to study the innermost regions of the ultra-compact jet. Their results reveal a helical geometry in the inner jet, anchored to a stationary feature and evolving over about 8 years. The jet's bends are due to variations in the ejection angle, and the γ-ray emission results from relativistic outflows and interactions within the jet. More information can be found directly in the publication here.
Identifying synergies between ground-based radio and space-based X-ray imaging techniques
04 April 2024
Reconstructing images from noisy, incomplete data is a challenge in many scientific fields, including Very Long Baseline Interferometry (VLBI) and the Spectrometer/Telescope for Imaging X-rays (STIX). A study led by MPIfR junior researcher Hendrik Müller explores the untapped potential of combining imaging techniques from both fields to improve high-resolution, high-fidelity imaging. By organising a semi-blind imaging challenge using typical VLBI and STIX data, the researchers compared seventeen algorithms from six different frameworks. The results showed that methods developed for STIX worked well with VLBI data and vice versa, significantly outperforming the traditional CLEAN algorithm. While entropy-based and Bayesian methods excelled on STIX data, more complex algorithms with multiple regularisation terms proved superior on VLBI data. This synergy suggests a promising future for joint progress, guiding the development of novel imaging algorithms in both fields. More information can be found in the original paper here.
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)
Magnetic and thermal acceleration in the jet of galaxy NGC 315
22 March 2024
A study led by MPIfR junior researcher Luca Ricci shows how relativistic jets from active galactic nuclei, such as those in NGC 315, reach high velocities on scales of a few to tens of parsecs. Traditionally, the focus has been on magnetic acceleration, while thermal acceleration has been considered negligible beyond compact regions near the central engine. Using a 2D relativistic magnetohydrodynamical code, the researchers studied jet acceleration from sub-parsec to parsec scales, based on observational data from very long baseline interferometry. The results show that when the thermal energy rivals or exceeds the magnetic energy, the thermal acceleration remains significant even at parsec scales, expanding the acceleration range. The study found that expansion drives the acceleration, and that disc-driven winds could be crucial for jet propagation. For NGC 315, models with different magnetic field configurations and shear layer thicknesses successfully replicated the observed acceleration and jet angles, highlighting the potential role of thermal acceleration in jet dynamics. More information can be found in the original paper in the journal Astronomy & Astrophysics here.
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).