This system, designated ZS7, has provided critical evidence through Webb’s unparalleled observational capabilities.
In our cosmic neighborhood, astronomers have discovered
supermassive black holes, much larger than the Sun, residing in many big
galaxies like our Milky Way. These colossal black holes have had a significant
influence on how their galaxies evolved, but the reasons behind their rapid
growth remain a major focus of scientific investigation.
Now, researchers using the James Webb Space Telescope (JWST)
have made a surprising find. They’ve detected the most distant black hole
merger ever seen.
This finding, happening when the universe was only 740
million years old, marks the farthest detection ever of black hole merging.
It’s also the earliest instance of such a phenomenon observed in space.
The discovery of such huge black holes so soon after the Big
Bang means they grew very quickly.
Dr Hannah Ubler, the lead author from Cambridge’s Cavendish
Laboratory and Kavli Institute for Cosmology, highlighted the significance of
these findings. “We found evidence for very dense gas with fast motions in the
vicinity of the black hole, as well as hot and highly ionised gas illuminated
by the energetic radiation typically produced by black holes in their accretion
episodes,” Übler explained in a press release.
Discovering ZS7
The JWST’s recent observations have pinpointed an ongoing
merger of two galaxies and their respective supermassive black holes, situated
at a time when the Universe was just 740 million years old. This system
designated ZS7, has provided critical evidence through Webb’s unparalleled
observational capabilities.
Astronomers can identify actively feeding black holes by
studying their special spectrographic features. However, these features can’t
be seen from Earth-based observatories and can only be spotted using JWST’s
advanced tools for galaxies as far away as the ones in this study.
Observations with JWST
Ubler mentioned that Webb’s exceptional imaging precision
enabled their team to spatially distinguish the two black holes.
One of the black holes in the ZS7 system boasts a mass
equivalent to 50 million Suns. “The mass of the other black hole is likely
similar, although it is much harder to measure because this second black hole
is buried in dense gas,” noted Professor Roberto Maiolino, also from the Kavli
Institute.
Role of merging in black hole growth
These findings suggest that merging plays a crucial role in
the rapid growth of black holes, even at the cosmic dawn. “Together with other
Webb findings of active, massive black holes in the distant Universe, our
results also show that massive black holes have been shaping the evolution of
galaxies from the very beginning,” Ubler remarked.
When these two black holes merge, they will create
gravitational waves, which are ripples in spacetime. Future observatories like
the Laser Interferometer Space Antenna (LISA), recently approved by the
European Space Agency as the first space-based observatory for studying
gravitational waves, will detect these waves.
Future prospects and studies
This amazing discovery came from the Galaxy Assembly program
using NIRSpec Integral Field Spectroscopy. Now, the team has earned another
chance to study more with JWST’s Cycle 3.
This research will explore the connection between massive
black holes and their host galaxies in the first billion years, focusing on
finding and studying black hole mergers, their frequency in early cosmic
history, and their role in black hole growth and gravitational wave production.
MIT’s insights on primordial black holes
In another study, MIT astronomers used the JWST to study
distant quasars, revealing insights into the origins of black holes. Their
observations, spanning over 13 billion years, showed that the black holes
powering these quasars were much larger than their host galaxies, sparking
questions about their rapid growth.
Minghao Yue from MIT’s Kavli Institute suggests these black
holes may have originated from “seed black holes” that quickly consumed
material. These primordial seeds, possibly formed from supernovae or direct
collapse of gas clouds, could have grown into massive black holes by consuming
cosmic matter.
MIT’s findings suggest that black holes may have gained mass
before their host galaxies in the early universe, challenging previous
assumptions.
Reference: Both research results have been published in the Monthly Notices of the Royal Astronomical Society and the Astrophysical Journal.