Closest pair of supermassive black holes yet

Date:
November 30, 2021
Source:
ESO
Summary:
Astronomers have revealed the closest pair of supermassive black
holes to Earth ever observed. The two objects also have a much
smaller separation than any other previously spotted pair of
supermassive black holes and will eventually merge into one giant
black hole.



FULL STORY ========================================================================== Using the European Southern Observatory's Very Large Telescope (ESO's
VLT), astronomers have revealed the closest pair of supermassive black
holes to Earth ever observed. The two objects also have a much smaller separation than any other previously spotted pair of supermassive black
holes and will eventually merge into one giant black hole.


========================================================================== Voggel and her team were able to determine the masses of the two objects
by looking at how the gravitational pull of the black holes influences
the motion of the stars around them. The bigger black hole, located right
at the core of NGC 7727, was found to have a mass almost 154 million
times that of the Sun, while its companion is 6.3 million solar masses.

It is the first time the masses have been measured in this way for a supermassive black hole pair. This feat was made possible thanks to the
close proximity of the system to Earth and the detailed observations the
team obtained at the Paranal Observatory in Chile using the Multi-Unit Spectroscopic Explorer (MUSE) on ESO's VLT, an instrument Voggel learnt
to work with during her time as a student at ESO. Measuring the masses
with MUSE, and using additional data from the NASA/ESA Hubble Space
Telescope, allowed the team to confirm that the objects in NGC 7727 were
indeed supermassive black holes.

Astronomers suspected that the galaxy hosted the two black holes, but
they had not been able to confirm their presence until now since we do
not see large amounts of high-energy radiation coming from their immediate surroundings, which would otherwise give them away. "Our finding implies
that there might be many more of these relics of galaxy mergers out there
and they may contain many hidden massive black holes that still wait to be found," says Voggel. "It could increase the total number of supermassive
black holes known in the local Universe by 30 percent." The search for similarly hidden supermassive black hole pairs is expected to make a great
leap forward with ESO's Extremely Large Telescope (ELT), set to start
operating later this decade in Chile's Atacama Desert. "This detection
of a supermassive black hole pair is just the beginning," says co-author Steffen Mieske, an astronomer at ESO in Chile and Head of ESO Paranal
Science Operations. "With the HARMONI instrument on the ELT we will be
able to make detections like this considerably further than currently
possible. ESO's ELT will be integral to understanding these objects." ========================================================================== Story Source: Materials provided by ESO. Note: Content may be edited
for style and length.


========================================================================== Related Multimedia:
* Views_of_the_nearest_pair_of_supermassive_black_holes ========================================================================== Journal Reference:
1. K. T. Voggel, A. C. Seth, H. Baumgardt, B. Husemann, N. Neumayer, M.

Hilker, R. Pechetti, S. Mieske, A. Dumont, I. Georgiev. First
direct dynamical detection of a dual super-massive black hole
system at sub-kpc separation. Astronomy & Astrophysics, 2021; DOI:
10.1051/0004-6361/ 202140827 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211130084331.htm

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