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Animations: NASA Telescopes Support Event Horizon Telescope in Studying Milky Way's Black Hole
A Tour of Sagittarius A*
(Credit: NASA/CXC/A. Hobart)
[Runtime: 04:33]

With closed-captions (at YouTube)

As the Event Horizon Telescope — known as the EHT — collected data for its remarkable new image of the Milky Way's supermassive black hole, a legion of other telescopes including three NASA X-ray observatories in space was also watching.

Astronomers are using these observations to learn more about how the black hole in the center of the Milky Way galaxy — known as Sagittarius A * (Sgr A* for short) — interacts with, and feeds off, its environment some 27,000 light-years from Earth.

While the EHT observed Sgr A* in April 2017 to make the new image, scientists in the collaboration also peered at the same black hole with facilities that detect different wavelengths of light. In this multiwavelength observing campaign, they assembled X-ray data from NASA's Chandra X-ray Observatory, Nuclear Spectroscopic Telescope, or NuSTAR, and the Neil Gehrels Swift Observatory. Telescopes outside of NASA involved included the East Asian Very Long-Baseline Interferometer, or VLBI, network that observed radio emission. There was also the Global 3-millimeter VLBI array along with infrared data from the European Southern Observatory's Very Large Telescope in Chile.

One important goal of this so-called multi-wavelength observing campaign was to catch X-ray flares, which are thought to be driven by magnetic processes similar to those seen on the Sun, but can be tens of millions of times more powerful. These flares occur approximately daily within the area of sky observed by the EHT, a region slightly larger than the event horizon of Sgr A*, the point of no return for matter falling inward. Another goal was to gain a critical glimpse of what is happening on larger scales. While the EHT result shows striking similarities between Sgr A* and the previous black hole it imaged, M87*, the wider picture is much more complex.

Both of these goals were successfully met. The researchers managed to catch X-ray flares — or outbursts — from Sgr A* during the EHT observations: a faint one seen with Chandra and Swift, and a moderately bright one seen with Chandra and NuSTAR. Astronomers have seen X-ray flares with a similar brightness to the latter with Chandra, but this is the first time that the EHT simultaneously observed Sgr A*. This offers an extraordinary opportunity to identify the responsible mechanism using actual images.

Astronomers were also able to learn more about the wider and complex picture of accretion. One of the biggest ongoing questions surrounding black holes is exactly how they collect, ingest, or even expel material orbiting them at near light speed, in a process known as "accretion." This process is fundamental to the formation and growth of planets, stars, and black holes of all sizes, throughout the universe.

Scientists will be able to use the data being released today to improve and hone their theoretical models of how black holes behave and interact with their surroundings. They will continue to study this unique combination to learn more about Sgr A* and black holes throughout our Universe.


A Quick Look at Sagittarius A*
(Credit: NASA/CXC/A. Hobart)
[Runtime: 00:45]

The Event Horizon Telescope captured an image of the Milky Way's giant black hole.

At the same time, other telescopes were observing the black hole too.

NASA's Chandra X-ray Observatory was key in this coordinated campaign.

These combined data reveal more about this black hole and its environment.





Sagittarius A* EHT Radio Sonification
Sonification Credit: NASA/CXC/SAO/K.Arcand, SYSTEM Sounds (M. Russo, A. Santaguida);
Image Credit: Radio: EHT Collaboration; X-ray (NASA/CXC/SAO); Infrared (NASA/HST/STScI)

[Runtime: 00:32]

arrow icon Audio Only Versions

This is a sonification — translation into sound — of the latest image from the Event Horizon Telescope of the supermassive black hole at the center of the Milky Way called Sagittarius A* (Sgr A*). Using a radar-like scan, the sonification begins at the 12 o'clock position and sweeps clockwise. Changes in volume represent the differences in brightness the EHT observed around the event horizon of Sgr A*. The material that is closer to the black hole and hence moving faster corresponds to higher frequencies of sound. This sonification was processed in a special way to allow a listener to hear the data in 3D stereo sound, in which the sounds seem to start directly ahead and then move clockwise to one ear then the other as the sweep is made.

About the Sound:

  • This is a radar-like scan, starting from 12 o'clock and moving clockwise.
  • The brightness controls the volume and the radial position controls the frequencies that are present.
  • The emission from material closer to the black hole (which orbits faster) is mapped to higher frequencies.
  • The sound is rendered in binaural audio. When listened to with headphones, the sound will appear to start directly in front of you and then move clockwise all the way around your head.
  • Listen for the three bright regions at about 1, 5, and 9 o'clock, as well as the very low tones indicating fainter light from outside the main ring.





animation
X-ray
(Download )
animation
Near-infrared
(Download )
animation
Mid-infrared
(Download )



Sagittarius A* Multiwavelength Sonification
Sonification Credit: NASA/CXC/SAO/K.Arcand, SYSTEM Sounds (M. Russo, A. Santaguida);
Image Credit: Radio: EHT Collaboration; X-ray (NASA/CXC/SAO); Infrared (NASA/HST/STScI)

[Runtime: 00:32]

arrow icon Audio Only Versions

This image shows the region around the Milky Way's central supermassive black hole, known as Sagittarius A* (Sgr A*), in infrared (orange and purple) and X-ray light (blue). The image is scanned from left to right and the data are transformed into sound. The brightness of the objects is represented by the volume, while the vertical positions of the sources in the image are mapped to musical pitches. X-rays are played with a soft synthesizer and the infrared data are heard as bass notes and plucked sounds. The brightest region in the middle of the image (and hence the loudest) is where Sgr A* the black hole, resides. It is within this area that the Event Horizon Telescope was able to peer to obtain the first image of Sgr A* itself.

About the Sound:

  • The image is scanned from left to right with brightness controlling the volume.
  • The vertical position is mapped to musical pitches with higher pitches toward the top.
  • The mid-IR layer is limited to a low range and played on a bass.
  • The X-ray layer is limited to a high range and played on a soft synth.
  • The brightest regions in the X-ray image (including Sgr A*) are highlighted by increasing the brightness of the synth's sound.
    • Listen for a peak at the location of the supermassive black hole Sagittarius A* at the 14 second mark.
  • The near IR layer covers the full pitch range.
  • The stars visible in the near-IR image are played on a plucked distorted synth.
  • The stereo pan follows the scan from left to right.

Zoom Into the Center of the Milky Way
(Credit: N. Risinger (skysurvey.org); DSS; ESO/Nogueras-Lara et al.; NASA/CXC; ESO/MPE/GRAVITY collaboration/L. Cal├žada; EHT Collaboration. Video compilation: NASA/CXC/A.Jubett)
[Runtime: 01:25]

A sequence of images and videos zooming into the supermassive black hole at the center of the Milky Way. The animation begins with a wide view of the Milky Way in visible light, followed by zooming into infrared images, then a pair of Chandra X-ray images of different sizes. The sequence continues zooming into a pair of videos showing the motions of stars orbiting around Sgr A* in infrared images. The animation finally zooms into the new EHT image. Also shown are squares that decrease in size by factors of ten, beginning with 10 light-years.


Sagittarius A* Flare Timelapse (Labeled)
(Credit: NASA/CXC/A. Hobart)
[Runtime: 00:02]

This video shows four Chandra X-ray Observatory images of the center of the Milky Way Galaxy, obtained on 2017 April 6th, 7th, 11th and 12th. The X-ray source associated with supermassive black hole Sgr A* is labeled. These X-rays come from the hot gas falling towards the black hole, rather than the black hole itself. An X-ray flare from Sgr A* is seen on April 11th.


Sagittarius A* Flare Timelapse (Unlabeled)
(Credit: NASA/CXC/A. Hobart)
[Runtime: 00:02]

This video shows four Chandra X-ray Observatory images of the center of the Milky Way Galaxy, obtained on 2017 April 6th, 7th, 11th and 12th. The X-ray source associated with supermassive black hole Sgr A* is labeled. These X-rays come from the hot gas falling towards the black hole, rather than the black hole itself. An X-ray flare from Sgr A* is seen on April 11th.


Visualization of Matter Near Sagittarius A* (Sgr A*)
(Credit: Koushik Chatterjee (BHI, Harvard University) using code H-AMR (Liska et al. 2019). For more details of these simulations of Sgr A* and its flaring see Chatterjee et al. (2021) and Ripperda et al. (2022).)
[Runtime: 00:11]

A 3D visualization of matter near a black hole, based on a computer simulation incorporating the physics of flowing gas, and the effects of magnetic fields and Einstein's General Theory of Relativity. The visualization shows gas orbiting and falling towards the black hole in a disk, and some gas being ejected in a jet. The black hole's event horizon, the point of no return for matter falling inwards, is represented by the black sphere. The disk is shown in colors representing gas density (ranging over a factor of 15 from purple to green), while the jet is shown in colors representing how strong the magnetic field is (ranging over a factor of 10 from gray to white). Thin, helix-shaped magnetic field lines are shown in white. Both the jet and magnetic fields originate in a region just outside the event horizon. The gas in the disk is extremely turbulent, producing small swirls of gas that are heated by a process called magnetic reconnection, like what occurs in flares on the Sun. These hot spots are shown in colors representing gas temperature (ranging over a factor of 5 from red to orange) and produce X-ray flares similar to what is seen in Sgr A*.





Audio Only Versions (Downloads)


Sagittarius A* EHT Sonification:
MP3 OGG M4R
Radio .mp3 .ogg .m4r


Sagittarius A* Multiwavelength Sonification:
MP3 OGG M4R
All Wavelengths .mp3 .ogg .m4r
X-ray .mp3 .ogg .m4r
Near-infrared .mp3 .ogg .m4r
Mid-infrared .mp3 .ogg .m4r





Return to: NASA Telescopes Support Event Horizon Telescope in Studying Milky Way's Black Hole (May 12, 2022)