STScI: Secrets of Turbulent Black Hole

[orin stepanek]

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ABOUT THIS IMAGE:
A fleet of spacecraft including NASA's Hubble Space Telescope has uncovered unprecedented details in the surroundings of a supermassive black hole. Observations reveal huge bullets of gas being driven away from the gravitational monster and a corona of very hot gas hovering above the disk of matter that is falling into the black hole.

A team led by Jelle Kaastra of SRON Netherlands Institute for Space Research made use of data from ESA's XMM-Newton and INTEGRAL spacecraft (which study X-rays and gamma rays, respectively), the Hubble Space Telescope (for ultraviolet observations with the COS instrument), and NASA's Chandra (X-ray) Observatory and Swift (gamma-ray) satellites.

The black hole that the team chose to study lies at the heart of the galaxy Markarian 509 (Mrk 509), 500 million light-years away. This black hole is colossal, containing 300 million times the mass of the Sun, and is growing more massive every day as it continues to feed on surrounding matter, which glows brightly as it forms a rotating disk around the black hole. Mrk 509 was chosen because it is known to vary in brightness, which indicates that the flow of matter is turbulent.

This image of Mrk 509 was taken in April 2007 with Hubble's Wide Field Planetary Camera 2. But using a large number of telescopes that are sensitive to different wavelengths of light gave astronomers unprecedented coverage running from the infrared, through the visible, ultraviolet, X-rays, and into the gamma-ray band.

The study is presented in a series of seven papers in the journal Astronomy and Astrophysics, with more expected to be published in coming months.

A full account of the research can be read on the SRON website at http://www.sron.nl .

Object Names: Markarian 509, Mrk 509

Image Type: Astronomical


Image Credit: NASA, ESA, G. Kriss (STScI), and J. de Plaa (SRON Netherlands Institute for Space Research)

Acknowledgment: B. Peterson (Ohio State University)

Science Credit: NASA, ESA, J. Kaastra (SRON Netherlands Institute for Space Research),

[bystander]

Dissecting a Black Hole's Surroundings
ESA/HEIC | SpaceTelescope.org | 2011 Sept 29

ESA spacecraft reveal new anatomy around a black hole
ESA Space Science | 2011 Sept 29

Space Telescopes Reveal Secrets of Turbulent Black Hole
NASA/STScI | HubbleSite.org | 2011 Sept 29

Space telescopes reveal secrets of turbulent black hole
Netherlands Institute for Space Research (SRON) | 2011 Sept 29

Supermassive black holes at the hearts of active galaxies swallow large amounts of gas. During this feast they spill a lot of their 'food', which is discharged in turbulent outbursts. An international team of astronomers has revealed some striking features of such an outburst around a supermassive black hole in a distant galaxy. They found a very hot 'convertor' corona hovering above the black hole and cold gas 'bullets' in hotter diffuse gas, speeding outwards with velocities up to 700 km/s.

Unlike popular belief, not all the matter around a black hole is swallowed up. A disc of infalling gas forms around the black hole. On the journey inwards the gas and dust emit large amounts of X-ray and UV radiation. This radiation can be so strong that it diverts a part of the gas inflow. It causes winds flowing outward with velocities up to several hundreds of km/s. An international team of astronomers led by Dr. Jelle Kaastra from the SRON Netherlands Institute for Space Research took the opportunity to observe and map such an extreme environment around one of the brightest supermassive black holes known to us. This 'monster' black hole - in the distant galaxy Markarian 509 - has a mass 300 million times that of the Sun. See an animated short film on this phenomenon A journey into black hole winds (Credit: Nahum Arav (CU Boulder)).

[i]Turbulent winds of gas swirl around a black hole. Some of the gas is spiraling inward toward the black hole, but another part is blown away (Credit: NASA/CXC/M.Weiss)[/i]

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Convertor corona

The Markarian 509 black hole is surrounded by a disc of gas shining bright in ultraviolet light. This emission varies in a synchronised way with emissions observed at the low end of the X-ray band, some 100s of times higher in energy than visible light. "The only way to explain this is by having gas hotter than that in the disc, a so-called 'corona', hovering above the disc," Jelle Kaastra says. "This corona absorbs and reprocesses the ultraviolet light from the disc, energising it and converting it into X-ray light. It must have a temperature of a few million degrees. Using five space telescopes, which enabled us to observe the area in unprecedented detail, we actually discovered a very hot 'corona' of gas hovering above the disc. This discovery allows us to make sense of some of the observations of active galaxies that have been hard to explain so far."

Cold gas bullets

The X-ray spectrum obtained with the Reflection Grating Spectrometer (RGS) of the space telescope XMM-Newton is the best obtained so far of such a system. It reveals unprecedented details of its gaseous environment. For the first time it has been possible to show that the outflow consists of at least five distinct components with temperatures ranging between 20.000 to a million degrees. The superb ultraviolet spectrum obtained by the Cosmic Origins Spectrograph of the Hubble Space Telescope reveals that the coolest gas in the line of sight towards Markarian 509 has 14 different velocity components at various locations in the innermost parts of this galaxy. Thus far only seven velocity components were identified.

The combined X-ray and UV measurements demonstrate that most of the visible outflowing gas is blown off from a dusty gas torus surrounding the central region more than 15 light years away from the black hole. This outflow consists of dense, cold blobs or gas bullets embedded in hotter diffuse gas. "Even at a distance of 15 light years, the energy released near the black hole manages to blow off gas from the dusty torus that surrounds the disc of infalling gas," Kaastra says.

[i]Edited Hubble Space Telescope image of Markarian 509. The bright core of the galaxy around the supermassive black hole is much brighter than the rest of the galaxy. Strong winds are emitted from the central region (Credit: MAST/SRON)[/i]

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Signs of cosmic collision

Further outwards, the signatures of the interstellar gas of the host galaxy are seen. That gas is strongly ionised by the central X-ray source: atoms are stripped of some or most of their electrons when illuminated by the powerful flux of X-rays. Even further out, at hundred thousands of light years, the X-ray light shines through gas falling in towards Markarian 509 with speeds of 200 km/s. This gas may point at a collision with a smaller galaxy in the past, that may have triggered the activity of Markarian 509.

Space telescopes

Five large space telescopes were involved in this hundred days campaign that took place in late 2009. The heart of the campaign consisted of repeated visible, X-ray and gamma-ray observations with ESA's XMM-Newton and INTEGRAL satellites, which monitored Markarian 509 for six weeks. This was followed by long observations with NASA's Chandra X-ray satellite, using the Low Energy Transmission Grating, and the NASA/ESA Hubble Space Telescope using the new Cosmic Origins Spectrograph. Prior to these observations short snapshots to monitor the behaviour of the source at all wavelengths were taken with the Swift satellite.

The combined efforts of all these instruments and astronomers gave an unprecedented insight into the core of an active galaxy. Right in the middle of the campaign the source went into outburst. The physical changes due to this outburst could be followed over the electromagnetic spectrum from visible light to X-rays.

Papers

The international consortium responsible for this campaign consists of 26 astronomers from 21 institutes on 4 continents. The first results of this campaign will be published as a series of 7 papers in Astronomy and Astrophysics, titled Multiwavelength campaign on Mrk 509. More results are in preparation.

Multiwavelength campaign on Mrk 509 - Astronomy and Astrophysics 534 (Oct 2011)

• I. Variability and spectral energy distribution - J. S. Kaastra et al
  • A&A 534 A36 (Oct 2011) DOI: 10.1051/0004-6361/201116869
    arXiv.org > astro-ph > arXiv:1107.0656 > 04 Jul 2011
  II. Analysis of high-quality Reflection Grating Spectrometer spectra - J. S. Kaastra et al
  • A&A 534 A37 (Oct 2011) DOI: 10.1051/0004-6361/201116870
    arXiv.org > astro-ph > arXiv:1107.0657 > 04 Jul 2011
  III. The 600 ks RGS spectrum: unravelling the inner region of an AGN - R. G. Detmers et al
  • A&A 534 A38 (Oct 2011) DOI: 10.1051/0004-6361/201116899
    arXiv.org > astro-ph > arXiv:1107.0658 > 04 Jul 2011
  IV. Optical-UV-X-ray variability and the nature of the soft X-ray excess - M. Mehdipour et al
  • A&A 534 A39 (Oct 2011) DOI: 10.1051/0004-6361/201116875
    arXiv.org > astro-ph > arXiv:1107.0659 > 04 Jul 2011
  V. Chandra-LETGS observation of the ionized absorber - J. Ebrero et al
  • A&A 534 A40 (Oct 2011) DOI: 10.1051/0004-6361/201117067
    arXiv.org > astro-ph > arXiv:1107.0660 > 04 Jul 2011
  VI. HST/COS observations of the far-ultraviolet spectrum - G. A. Kriss et al
  • A&A 534 A41 (Oct 2011) DOI: 10.1051/0004-6361/201117123
    arXiv.org > astro-ph > arXiv:1107.0661 > 04 Jul 2011
  VII. Relative abundances of the warm absorber - K. C. Steenbrugge et al
  • A&A 534 A42 (Oct 2011) DOI: 10.1051/0004-6361/201117304
    arXiv.org > astro-ph > arXiv:1108.2488 > 11 Aug 2011

[Chris Peterson]

Crummy headline writing. A black hole can't be turbulent... the concept doesn't even make sense. What is happening (as the articles themselves make clear) is that the gravitational and kinetic energy of a black hole is driving turbulence in the surrounding medium.