Flaring black hole whips up ultra-fast winds

Artist’s impression of the flaring, windy black hole in NGC 3783 (portrait)
Credit: ESA - Acknowledgements: ATG Europe
Licence: CC BY-SA 3.0 IGO or ESA Standard Licence
(content can be used under either licence)

An artist's impression of XMM-Newton.
Credit: ESA-C. Carreau
Licence: CC BY-SA 3.0 IGO or ESA Standard Licence
(content can be used under either licence)

XRISM spacecraft
Credit: JAXA
ESA Standard Licence

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Leading X-ray space telescopes XMM-Newton and XRISM have spotted an extraordinary blast from a supermassive black hole. In a matter of hours, the gravitational monster whipped up powerful winds, flinging material out into space at eye-watering speeds of 60 000 km per second.

The gigantic black hole lurks within NGC 3783, a beautiful spiral galaxy imaged recently by the NASA/ESA Hubble Space Telescope. Astrono.mers spotted a bright X-ray flare erupt from the black hole before swiftly fading away. As i,brt faded, fast winds emerged, raging at one-fifth of the speed of light.

“We’ve not watched a black hole create winds this speedily before,” says lead researcher Liyi Gu at Space Research Organisation Netherlands (SRON). “For the first time, we’ve seen how a rapid burst of X-ray light from a black hole immediately triggers ultra-fast winds, with these winds forming in just a single day.”

Devouring material

To study NGC 3783 and its black hole, Gu and colleagues simultaneously used the European Space Agency’s XMM-Newton and the X-Ray Imaging and Spectroscopy Mission (XRISM), a JAXA-led mission with ESA and NASA participation.

The black hole in question is as massive as 30 million Suns. As it feasts on nearby material, it powers an extremely bright and active region at the heart of the spiral galaxy. This region, known as an Active Galactic Nucleus (AGN), blazes in all kinds of light, and throws powerful jets and winds out into the cosmos.

“AGNs are really fascinating and intense regions, and key targets for both XMM-Newton and XRISM,” adds Matteo Guainazzi, ESA XRISM Project Scientist and co-author of the discovery.

“The winds around this black hole seem to have been created as the AGN’s tangled magnetic field suddenly ‘untwisted’ – similar to the flares that erupt from the Sun, but on a scale almost too big to imagine.”

A little less alien

The winds from the black hole resemble large solar eruptions of material known as coronal mass ejections, which form as the Sun hurls streams of superheated material into space. In this way, the study shows that supermassive black holes sometimes act like our own star, making these mysterious objects seem a little less alien.

In fact, a coronal mass ejection following an intense flare was spotted at the Sun as recently as 11 November, with the winds associated with this event thrown out at initial speeds of 1500 km per second.

“Windy AGNs also play a big role in how their host galaxies evolve over time, and how they form new stars,” adds Camille Diez, a team member and ESA Research Fellow.

“Because they’re so influential, knowing more about the magnetism of AGNs, and how they whip up winds such as these, is key to understanding the history of galaxies throughout the Universe.”

A joint discovery

XMM-Newton has been a pioneering explorer of the hot and extreme Universe for over 25 years, while XRISM has been working to answer key open questions about how matter and energy move through the cosmos since it launched in September 2023.

The two X-ray space telescopes worked together to uncover this unique event and understand the black hole’s flare and winds. XMM-Newton tracked the evolution of the initial flare with its Optical Monitor, and assessed the extent of the winds using its European Photon Imaging Camera (EPIC). XRISM spotted the flare and winds using its Resolve instrument, also studying the winds’ speed, structure, and figuring out how they were launched into space.

“Their discovery stems from successful collaboration, something that’s a core part of all ESA missions,” says ESA XMM-Newton Project Scientist Erik Kuulkers.

“By zeroing in on an active supermassive black hole, the two telescopes have found something we’ve not seen before: rapid, ultra-fast, flare-triggered winds reminiscent of those that form at the Sun. Excitingly, this suggests that solar and high-energy physics may work in surprisingly familiar ways throughout the Universe.”

Source: ESA/Science Exploration

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Notes for editors

‘Delving into the depths of NGC 3783 with XRISM: III. Birth of an ultrafast outflow during a soft flare’ by Liyi Gu et al. is published today in Astronomy & Astrophysics.

SRON news release

For more information, please contact:
ESA Media Relations
media@esa.int

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The eponymous NGC 3783

NGC 3783

A spiral galaxy, seen face-on to the viewer. The bright centre of the galaxy is crossed by a glowing bar, and it is surrounded by tightly-wound spiral arms, forming a circular shape with relatively clear edges. Faraway galaxies can be seen around it, along with a few bright stars, on a dark background. One star to the right of the galaxy is very large and extremely bright with long diffraction spikes around it. Credit:  ESA/Hubble & NASA, M. C. Bentz, D. J. V. Rosario

This image features NGC 3783, a bright barred spiral galaxy about 130 million light-years from Earth, that also lends its name to the eponymous NGC 3783 galaxy group. Like galaxy clusters, galaxy groups are aggregates of gravitationally bound galaxies. Galaxy groups, however, are less massive and contain fewer members than galaxy clusters do: where galaxy clusters can contain hundreds or even thousands of constituent galaxies, galaxy groups do not typically include more than 50. The Milky Way is actually part of a galaxy group, known as the Local Group, which contains two other large galaxies (Andromeda and the Triangulum galaxy), as well as several dozen satellite and dwarf galaxies. The NGC 3783 galaxy group, meanwhile, contains 47 galaxies. It also seems to be at a fairly early stage of its evolution, making it an interesting object of study.

Whilst the focus of this image is the spiral galaxy NGC 3783, the eye is equally drawn to the very bright object in the lower right part of this image. This is the star HD 101274. The perspective in this image makes the star and the galaxy look like close companions, but this is an illusion. HD 101274 lies only about 1530 light-years from Earth, meaning it is about 85 thousand times closer than NGC 3783. This explains how a single star can appear to outshine an entire galaxy!

NGC 3783 is a type-1 Seyfert galaxy, which is a galaxy with a bright central region — so it’s particularly bright itself, as far as galaxies go. In this image it is recorded by Hubble in incredible detail, from its glowing central bar to its narrow, winding arms and the dust threaded through them, thanks to five separate images taken in different wavelengths of light. In fact, the galactic centre is bright enough to Hubble that it exhibits diffraction spikes, normally only seen on stars such as HD 101274.

Source: ESA/Hubble/potw

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Dusty Surprise Around Giant Black Hole

 PR Image eso1327a

Artist's impression of the surroundings of the supermassive black hole in NGC 3783

 

PR Image eso1327b

Wide-field view of the region around galaxy NGC 3783

 

PR Image eso1327c

The active galaxy NGC 3783 in the constellation of Centaurus

 

Videos

PR Video eso1327a

Outflow from active galaxy NGC 3783 (artist’s impression)

ESO’s Very Large Telescope Interferometer has gathered the most detailed observations ever of the dust around the huge black hole at the centre of an active galaxy. Rather than finding all of the glowing dust in a doughnut-shaped torus around the black hole, as expected, the astronomers find that much of it is located above and below the torus. These observations show that dust is being pushed away from the black hole as a cool wind — a surprising finding that challenges current theories and tells us how supermassive black holes evolve and interact with their surroundings.

Over the last twenty years, astronomers have found that almost all galaxies have a huge black hole at their centre. Some of these black holes are growing by drawing in matter from their surroundings, creating in the process the most energetic objects in the Universe: active galactic nuclei (AGN). The central regions of these brilliant powerhouses are ringed by doughnuts of cosmic dust [1] dragged from the surrounding space, similar to how water forms a small whirlpool around the plughole of a sink. It was thought that most of the strong infrared radiation coming from AGN originated in these doughnuts.

But new observations of a nearby active galaxy called NGC 3783, harnessing the power of the Very Large Telescope Interferometer (VLTI) at ESO’s Paranal Observatory in Chile [2], have given a team of astronomers a surprise. Although the hot dust — at some 700 to 1000 degrees Celsius — is indeed in a torus as expected, they found huge amounts of cooler dust above and below this main torus [3].

As Sebastian Hönig (University of California Santa Barbara, USA and Christian-Albrechts-Universität zu Kiel, Germany), lead author of the paper presenting the new results, explains, “This is the first time we’ve been able to combine detailed mid-infrared observations of the cool, room-temperature dust around an AGN with similarly detailed observations of the very hot dust. This also represents the largest set of infrared interferometry for an AGN published yet.”

The newly-discovered dust forms a cool wind streaming outwards from the black hole. This wind must play an important role in the complex relationship between the black hole and its environment. The black hole feeds its insatiable appetite from the surrounding material, but the intense radiation this produces also seems to be blowing the material away. It is still unclear how these two processes work together and allow supermassive black holes to grow and evolve within galaxies, but the presence of a dusty wind adds a new piece to this picture.

In order to investigate the central regions of NGC 3783, the astronomers needed to use the combined power of the Unit Telescopes of ESO’s Very Large Telescope. Using these units together forms an interferometer that can obtain a resolution equivalent to that of a 130-metre telescope.

Another team member, Gerd Weigelt (Max-Planck-Institut für Radioastronomie, Bonn, Germany), explains, “By combining the world-class sensitivity of the large mirrors of the VLT with interferometry we are able to collect enough light to observe faint objects. This lets us study a region as small as the distance from our Sun to its closest neighbouring star, in a galaxy tens of millions of light-years away. No other optical or infrared system in the world is currently capable of this.”

These new observations may lead to a paradigm shift in the understanding of AGN. They are direct evidence that dust is being pushed out by the intense radiation. Models of how the dust is distributed and how supermassive black holes grow and evolve must now take into account this newly-discovered effect.

Hönig concludes, “I am now really looking forward to MATISSE, which will allow us to combine all four VLT Unit Telescopes at once and observe simultaneously in the near- and mid-infrared — giving us much more detailed data.” MATISSE, a second generation instrument for the VLTI, is currently under construction.

Notes

[1] Cosmic dust consist of silicate and graphite grains — minerals also abundant on Earth. The soot from a candle is very similar to cosmic graphite dust, although the size of the grains in the soot are ten or more times bigger than typical grain sizes of cosmic graphite grains.

[2] The VLTI is formed from a combination of the four 8.2-metre VLT Unit Telescopes, or the four moveable 1.8-metre VLT Auxiliary Telescopes. It makes use of a technique known as interferometry, in which sophisticated instrumentation combines the light from several telescopes into one observation. Although it usually does not produce actual images, this technique dramatically increases the level of detail that can be measured in the resulting observations, comparable to what a space telescope with a diameter of over 100 metres would measure.

[3] The hotter dust was mapped using the AMBER VLTI instrument at near-infrared wavelengths and the newer observations reported here used the MIDI instrument at wavelengths between 8 and 13 microns in the mid-infrared.

More information

This research was presented in a paper entitled “Dust in the Polar Region as a Major Contributor to the Infrared Emission of Active Galactic Nuclei”, by S. Hönig et al., to appear in the Astrophysical Journal on 20 June 2013.

The team is composed of S. F. Hönig (University of California in Santa Barbara, USA [UCSB]; Christian-Albrechts-Universität zu Kiel, Germany), M. Kishimoto (Max-Planck-Institut für Radioastronomie, Bonn, Germany [MPIfR]), K. R. W. Tristram (MPIfR), M. A. Prieto (Instituto de Astrofísica de Canarias, Tenerife, Spain), P. Gandhi (Institute of Space and Astronautical Science, Kanawaga, Japan; University of Durham, United Kingdom), D. Asmus (MPIfR), R. Antonucci (UCSB), L. Burtscher (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), W. J. Duschl (Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Germany) and G. Weigelt (MPIfR).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links

• Research paper
• Photos of the VLT
• Information on the Very Large Telescope Interferometer (VLTI)

Contacts

Sebastian Hönig
University of California Santa Barbara
USA
Tel: +49 431 880 4108
Cell: +49 176 9995 0941
Email: shoenig@physics.ucsb.edu

Poshak Gandhi
University of Durham
United Kingdom
Email: poshak.gandhi@durham.ac.uk

Gerd Weigelt
Max-Planck-Institut für Radioastronomie
Bonn, Germany
Email: weigelt@mpifr.de

Wolfgang Duschl
Christian-Albrechts-Universität zu Kiel
Kiel, Germany
Email: wjd@astrophysik.uni-kiel.de

Fuel for the black hole

First investigations of a galactic nucleus with the AMBER instrument of the Very Large Telescope Interferometer in Chile


An international research team led by Gerd Weigelt from the Max-Planck-Institut für Radioastronomie in Bonn reports on high-resolution studies of an active galactic nucleus in the near-infrared. The observations were carried out with the Very Large Telescope Interferometer (VLTI) of the European Southern Observatory (ESO). The use of near-infrared interferometry allowed the team to resolve a ring-shaped dust distribution (generally called "dust torus") in the inner region of the nucleus of the active galaxy NGC 3783. This dust torus probably represents the reservoir of gaseous and dusty material that "feeds" the hot gas disk ("accretion disk") and the supermassive black hole in the center of this galaxy. The resolved dust torus has an angular radius of only 0.7 milli-arcseconds on the sky, an angle that is 5 million times smaller than one degree. This angular radius corresponds to a radius of approximately 0.5 light years for a distance of 150 million light years. Studies of the physical properties of these dust tori are very important to improve our understanding of their structure and interaction with the accretion disk. To obtain these measurements, the light from up to three telescopes of the Very Large Telescope Interferometer was interferometrically combined. This method is able to achieve an angular resolution equivalent to the resolution of a telescope with a diameter of 130 Meters.

Figure 1: Artist's view of a dust torus surrounding the accretion disk and the central black hole in active galactic nuclei. Credit: NASA E/PO - Sonoma State University, Aurore Simonnet (http://epo.sonoma.edu/). (Click here for higher resolution)

Extreme physical processes occur in the innermost regions of galactic nuclei. Supermassive black holes were discovered in many galaxies. The masses of these black holes are often a millionfold larger than the mass of our sun. These central black holes are surrounded by hot and bright gaseous disks, called "accretion disks". The emitted radiation from these accretion disks is probably generated by infalling material. To maintain the high luminosity of the accretion disk, fresh material has to be permanently supplied. The dust tori (see Fig. 1) surrounding the accretion disks are most likely the reservoir of the material that flows through the accretion disk and finally "feeds" the growing black hole.

Observations of these dust tori are very challenging since their sizes are very small. A giant telescope with a mirror diameter of more than 100 Meters would be able to provide the required angular resolution, but unfortunately telescopes of this size will not be available in the near future. This raises the question: Is there an alternative approach that provides the high resolution required?

The solution is to simultaneously combine ("interfere") the light from two or more telescopes since these multi-telescope images, which are called interferograms, contain high-resolution information. In the reported NGC 3783 observations, the AMBER interferometry instrument was used to combine the infrared light from two or three telescopes of ESO's Very Large Telescope Interferometer (VLTI, see Fig. 2). This interferometric method is able to achieve an extreme angular resolution that is proportional to the distance between the telescopes. Since the largest distance between the four telescopes of the VLTI is 130 Meters, an angular resolution is obtained that is as high as the theoretical resolution of a telescope with a mirror diameter of 130 Meters - a resolution that is 15 times higher than the resolution of one of the VLTI telescopes, which have a mirror diameter of 8 Meters.

"The ESO VLTI provides us with a unique opportunity to improve our understanding of active galactic nuclei,", says Gerd Weigelt from the Max-Planck-Institut für Radioastronomie in Bonn. "It allows us to study fascinating physical processes with unprecedented resolution over a wide range of infrared wavelengths. This is needed to derive physical properties of these sources."

And Makoto Kishimoto emphasizes: "We hope to obtain more detailed information in the next few years by additional observations at shorter wavelengths, with longer baselines, and with higher spectral resolution. Most importantly, in a few years, two further interferometric VLTI instruments will be available, which can provide complementary information."

To resolve the nucleus of the active galaxy NGC 3783, the research team recorded thousands of two- and three-telescope interferograms with the VLTI. The telescope distances were in the range of 45 to 114 Meters. The evaluation of these interferograms allowed the team to derive the radius of the compact dust torus in NGC 3783. A very small angular torus radius of 0.74 milli-arcsecond was measured, which corresponds to a radius of 0.52 light years. These near-infrared radius measurements, together with previously obtained mid-infrared measurements, allowed the team to derive important physical parameters of the torus of NGC 3783.

"The high resolution of the VLTI is also important for studying many other types of astrophysical key objects", underlines Karl-Heinz Hofmann. "It is clear that infrared interferometry will revolutionize infrared astronomy in a similar way as radio interferometry has revolutionized radio astronomy."

Fig. 2: The Very Large Telescope Interferometer of the European Southern Observatory.Photo: Gerd Weigelt/MPIfR. (Click here for higher resolution).

The research team comprises scientists from the Universities of Florence, Grenoble, Nice, Santa Barbara, and from the MPI für Radioastronomie.

Original Paper:

VLTI/AMBER observations of the Seyfert nucleus of NGC 3783, G. Weigelt, K.-H. Hofmann, M. Kishimoto, S. Hönig, D. Schertl, A. Marconi,, F. Millour, R. Petrov, D. Fraix-Burnet, F. Malbet, K. Tristram and M. Vannier, Astronomy & Astrophysics (Volume 541, L9, 2012). DOI: 10.1051/0004-6361/201219213.

Parallel Press Releases:

Buco nero in HD , Media INAF 16/05/2012 (in Italian)


Further Information:

Max-Planck-Institut für Radioastronomie (MPIfR)

Infrared Astronomy Group at MPIfR

European Southern Observatory (ESO)

AMBER - Astronomical Multi-BEam combineR, ESO Homepage

Astronomical Multi-BEam combineR, Grenoble Homepage

Institute for Planetology and Astrophysics (IPAG), Grenoble, France

Laboratoire Lagrange, Nice, France

Observatoire de la Côte d'Azur, Nice, France

Arcetri Astrophysical Observatory, Firenze, Italy

Department of Physics, UCSB, U.S.A.


Contact:

Prof. Dr. Gerd Weigelt,
Head of Research group "Infrared Astronomy",
Max-Planck-Institut für Radioastronomie, Bonn.
Fon: +49(0)228-525-243
E-mail: gweigelt@mpifr-bonn.mpg.de

Dr. Makoto Kishimoto,
Max-Planck-Institut für Radioastronomie:
Fon: +49(0)228-525-189
E-mail: mk@mpifr-bonn.mpg.de

Dr. Norbert Junkes,
Press and Public Outreach,
Max-Planck-Institut für Radioastronomie:
Fon: +49(0)228-525-399
E-mail: njunkes@mpifr-bonn.mpg.de