ESO telescopes record last moments of star devoured by a black hole


Date:
October 12, 2020
Source:
ESO
Summary:
Astronomers have spotted a rare blast of light from a star being
ripped apart by a supermassive black hole. The phenomenon, known
as a tidal disruption event, is the closest such flare recorded
to date at just over 215 million light-years from Earth, and has
been studied in unprecedented detail.



FULL STORY ========================================================================== [ESO's Very Large | Credit: (c) CPO / stock.adobe.com] ESO's Very Large Telescope complex in Paranal, Chile (stock image).

Credit: (c) CPO / stock.adobe.com [ESO's Very Large | Credit: (c) CPO / stock.adobe.com] ESO's Very Large Telescope complex in Paranal, Chile
(stock image).

Credit: (c) CPO / stock.adobe.com Close Using telescopes from the
European Southern Observatory (ESO) and other organisations around the
world, astronomers have spotted a rare blast of light from a star being
ripped apart by a supermassive black hole. The phenomenon, known as a
tidal disruption event, is the closest such flare recorded to date at
just over 215 million light-years from Earth, and has been studied in unprecedented detail. The research is published today in Monthly Notices
of the Royal Astronomical Society.


==========================================================================
"The idea of a black hole 'sucking in' a nearby star sounds like science fiction. But this is exactly what happens in a tidal disruption event,"
says Matt Nicholl, a lecturer and Royal Astronomical Society research
fellow at the University of Birmingham, UK, and the lead author of the
new study. But these tidal disruption events, where a star experiences
what's known as spaghettification as it's sucked in by a black hole,
are rare and not always easy to study. The team of researchers pointed
ESO's Very Large Telescope (VLT) and ESO's New Technology Telescope (NTT)
at a new flash of light that occurred last year close to a supermassive
black hole, to investigate in detail what happens when a star is devoured
by such a monster.

Astronomers know what should happen in theory. "When an unlucky star
wanders too close to a supermassive black hole in the centre of a galaxy,
the extreme gravitational pull of the black hole shreds the star into
thin streams of material," explains study author Thomas Wevers, an
ESO Fellow in Santiago, Chile, who was at the Institute of Astronomy, University of Cambridge, UK, when he conducted the work. As some of
the thin strands of stellar material fall into the black hole during
this spaghettification process, a bright flare of energy is released,
which astronomers can detect.

Although powerful and bright, up to now astronomers have had trouble investigating this burst of light, which is often obscured by a curtain
of dust and debris. Only now have astronomers been able to shed light
on the origin of this curtain.

"We found that, when a black hole devours a star, it can launch a powerful blast of material outwards that obstructs our view," explains Samantha
Oates, also at the University of Birmingham. This happens because the
energy released as the black hole eats up stellar material propels the
star's debris outwards.

The discovery was possible because the tidal disruption event the team
studied, AT2019qiz, was found just a short time after the star was
ripped apart.

"Because we caught it early, we could actually see the curtain of dust
and debris being drawn up as the black hole launched a powerful outflow
of material with velocities up to 10,000 km/s," says Kate Alexander,
NASA Einstein Fellow at Northwestern University in the US. "This unique
'peek behind the curtain' provided the first opportunity to pinpoint the
origin of the obscuring material and follow in real time how it engulfs
the black hole." The team carried out observations of AT2019qiz, located
in a spiral galaxy in the constellation of Eridanus, over a 6-month period
as the flare grew in luminosity and then faded away. "Several sky surveys discovered emission from the new tidal disruption event very quickly after
the star was ripped apart," says Wevers. "We immediately pointed a suite
of ground-based and space telescopes in that direction to see how the
light was produced." Multiple observations of the event were taken over
the following months with facilities that included X-shooter and EFOSC2, powerful instruments on ESO's VLT and ESO's NTT, which are situated in
Chile. The prompt and extensive observations in ultraviolet, optical,
X-ray and radio light revealed, for the first time, a direct connection
between the material flowing out from the star and the bright flare
emitted as it is devoured by the black hole. "The observations showed
that the star had roughly the same mass as our own Sun, and that it lost
about half of that to the monster black hole, which is over a million
times more massive," says Nicholl, who is also a visiting researcher at
the University of Edinburgh.

The research helps us better understand supermassive black holes and how
matter behaves in the extreme gravity environments around them. The team
say AT2019qiz could even act as a 'Rosetta stone' for interpreting future observations of tidal disruption events. ESO's Extremely Large Telescope
(ELT), planned to start operating this decade, will enable researchers to detect increasingly fainter and faster evolving tidal disruption events,
to solve further mysteries of black hole physics.


========================================================================== Story Source: Materials provided by ESO. Note: Content may be edited
for style and length.


========================================================================== Related Multimedia:
*
Images_and_videos_of_AT2019qiz,_including_animation_of_star_being_tidally
disrupted_by_a_black_hole ========================================================================== Journal Reference:
1. M Nicholl, T Wevers, S R Oates, K D Alexander, G Leloudas, F
Onori, A
Jerkstrand, S Gomez, S Campana, I Arcavi, P Charalampopoulos,
M Gromadzki, N Ihanec, P G Jonker, A Lawrence, I Mandel, S
Schulze, P Short, J Burke, C McCully, D Hiramatsu, D A Howell,
C Pellegrino, H Abbot, J P Anderson, E Berger, P K Blanchard, G
Cannizzaro, T-W Chen, M Dennefeld, L Galbany, S Gonza'lez-Gaita'n,
G Hosseinzadeh, C Inserra, I Irani, P Kuin, T Mu"ller-Bravo, J
Pineda, N P Ross, R Roy, S J Smartt, K W Smith, B Tucker, Ł
Wyrzykowski, D R Young. An outflow powers the optical rise of the
nearby, fast-evolving tidal disruption event AT2019qiz. Monthly
Notices of the Royal Astronomical Society, 2020; 499 (1): 482 DOI:
10.1093/mnras/staa2824 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201012115956.htm

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