Research Highlights
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
Astronomers have given us a look into the engine compartment of a quasar.
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.
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.
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
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.
Forschern gelangen Bilder von sogenannten Jets in einem Schwarzen Loch.
Italian
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.
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
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.
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
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
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.
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.
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.
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!
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.
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.
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.
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
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.
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.
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.
