Starlight and the first black holes: researchers detect the host
galaxies of quasars in the early universe

Date:
June 28, 2023
Source:
Kavli Institute for the Physics and Mathematics of the Universe
Summary:
For the first time, the James Webb Space Telescope has revealed
starlight from two massive galaxies hosting actively growing
black holes -- quasars -- seen less than a billion years after
the Big Bang.


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FULL STORY ==========================================================================
New images from the James Webb Space Telescope have revealed, for the
first time, starlight from two massive galaxies hosting actively growing
black holes -- quasars -- seen less than a billion years after the Big
Bang. A new study in Nature this week finds the black holes have masses
close to a billion times that of the Sun, and the host galaxy masses
are almost one hundred times larger, a ratio similar to what is found in
the more recent universe. A powerful combination of the Subaru Telescope
and the JWST has paved a new path to study the distant universe.

The existence of such massive black holes in the distant universe has
created more questions than answers for astrophysicists. How could these
black holes grow to be so large when the universe was so young? Even more puzzling, observations in the local universe show a clear relation between
the mass of supermassive black holes and the much larger galaxies in which
they reside. The galaxies and the black holes have completely different
sizes, so which came first: the black holes or the galaxies? This is a "chicken-or-egg" problem on a cosmic scale.

An international team of researchers, led by Kavli Institute for the
Physics and Mathematics of the Universe (Kavli IPMU) Project Researcher
Xuheng Ding and Professor John Silverman, and Peking University Kavli
Institute for Astronomy and Astrophysics (PKU-KIAA) Kavli Astrophysics
Fellow Masafusa Onoue have started to answer this question with the
James Webb Space Telescope (JWST), launched in December 2021. Studying
the relation between host galaxies and black holes in the early universe
allows scientists to watch their formation, and see how they are related
to one another.

Quasars are luminous, while their host galaxies are faint, which has made
it challenging for researchers to detect the dim light of the galaxy
in the glare of the quasar, especially at great distances. Before the
JWST, the Hubble Space Telescope was able to detect host galaxies of
luminous quasars when the universe was just under 3 billion years old,
but no younger.

The superb sensitivity and the ultra-sharp images of the JWST at infrared wavelengths finally allowed researchers to push these studies to the time
when the quasars and galaxies first formed. Just a few months after JWST started regular operations, the team observed two quasars, HSC J2236+0032
and HSC J2255+0251, at redshifts 6.40 and 6.34 when the universe was approximately 860 million years old. These two quasars were discovered
in a deep survey program of the 8.2m-Subaru Telescope on the summit of
Maunakea in Hawai'i. The relatively low luminosities of these quasars
made them prime targets for measurement of the host galaxy properties,
and the successful detection of the hosts represents the earliest epoch
to date at which starlight has been detected in a quasar.

The images of the two quasars were taken at infrared wavelengths of 3.56
and 1.50 micron with JWST's NIRCam instrument, and the host galaxies
became apparent after carefully modeling and subtracting glare from
the accreting black holes. The stellar signature of the host galaxy
was also seen in a spectrum taken by JWST's NIRSPEC for J2236+0032,
further supporting the detection of the host galaxy.

Analyses of the host galaxy photometry found that these two quasar host galaxies are massive, measuring 130 and 34 billion times the mass of
the Sun, respectively. Measuring the speed of the turbulent gas in the
vicinity of the quasars from the NIRSPEC spectra suggests that the black
holes that power them are also massive, measuring 1.4 and 0.2 billion
times the mass of the Sun. The ratio of the black hole mass to host
galaxy mass is similar to those of galaxies in the more recent past,
suggesting that the relationship between black holes and their hosts
was already in place 860 million years after the Big Bang.

Ding, Silverman, Onoue and their colleagues will continue this study
with a larger sample using scheduled Cycle 1 JWST observations, which
will then further constrain models for the coevolution of black holes
and their host galaxies. The team recently learned that they have been
awarded additional time for JWST in its next cycle to study the host
galaxy of J2236+0032 in much more detail.

Details of this study will be published in Nature on June 28.

* RELATED_TOPICS
o Space_&_Time
# Black_Holes # Galaxies # Astrophysics # Astronomy #
Cosmology # Big_Bang # Space_Telescopes # NASA
* RELATED_TERMS
o Quasar o Spitzer_space_telescope o Radio_telescope
o Big_Bang o Galaxy o Big_Bang_nucleosynthesis
o Cosmic_microwave_background_radiation o
Compton_Gamma_Ray_Observatory

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


========================================================================== Related Multimedia:
* Quasar_and_the_host_galaxy ========================================================================== Journal Reference:
1. Xuheng Ding, Masafusa Onoue, John D. Silverman, Yoshiki Matsuoka,
Takuma
Izumi, Michael A. Strauss, Knud Jahnke, Camryn L. Phillips,
Junyao Li, Marta Volonteri, Zoltan Haiman, Irham Taufik Andika,
Kentaro Aoki, Shunsuke Baba, Rebekka Bieri, Sarah E. I. Bosman,
Connor Bottrell, Anna- Christina Eilers, Seiji Fujimoto,
Melanie Habouzit, Masatoshi Imanishi, Kohei Inayoshi, Kazushi
Iwasawa, Nobunari Kashikawa, Toshihiro Kawaguchi, Kotaro Kohno,
Chien-Hsiu Lee, Alessandro Lupi, Jianwei Lyu, Tohru Nagao, Roderik
Overzier, Jan-Torge Schindler, Malte Schramm, Kazuhiro Shimasaku,
Yoshiki Toba, Benny Trakhtenbrot, Maxime Trebitsch, Tommaso Treu,
Hideki Umehata, Bram P. Venemans, Marianne Vestergaard, Fabian
Walter, Feige Wang, Jinyi Yang. Detection of stellar light from
quasar host galaxies at redshifts above 6. Nature, 2023; DOI:
10.1038/s41586-023-06345-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/06/230628125125.htm

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