Hubble unexpectedly finds double quasar in distant universe

Date:
April 5, 2023
Source:
NASA/Goddard Space Flight Center
Summary:
The early universe was a rambunctious place where galaxies often
bumped into each other and even merged together. Using NASA's Hubble
Space Telescope and other space and ground-based observatories,
astronomers investigating these developments have made an unexpected
and rare discovery: a pair of gravitationally bound quasars, both
blazing away inside two merging galaxies. They existed when the
universe was just 3 billion years old.


Facebook Twitter Pinterest LinkedIN Email
FULL STORY ==========================================================================
The early universe was a rambunctious place where galaxies often bumped
into each other and even merged together. Using NASA's Hubble Space
Telescope and other space and ground-based observatories, astronomers investigating these developments have made an unexpected and rare
discovery: a pair of gravitationally bound quasars, both blazing away
inside two merging galaxies.

They existed when the universe was just 3 billion years old.


========================================================================== Quasars are bright objects powered by voracious, supermassive black holes blasting out ferocious fountains of energy as they engorge themselves
on gas, dust, and anything else within their gravitational grasp.

"We don't see a lot of double quasars at this early time in the
universe. And that's why this discovery is so exciting," said graduate
student Yu-Ching Chen of the University of Illinois at Urbana-Champaign,
lead author of this study.

Finding close binary quasars is a relatively new area of research that
has just developed in the past 10 to 15 years. Today's powerful new observatories have allowed astronomers to identify instances where two
quasars are active at the same time and are close enough that they will eventually merge.

There is increasing evidence that large galaxies are built up through
mergers.

Smaller systems come together to form bigger systems and ever larger structures. During that process there should be pairs of supermassive
black holes formed within the merging galaxies. "Knowing about the
progenitor population of black holes will eventually tell us about the emergence of supermassive black holes in the early universe, and how
frequent those mergers could be," said Chen.

"We're starting to unveil this tip of the iceberg of the early binary
quasar population," said Xin Liu of the University of Illinois at Urbana-Champaign.

"This is the uniqueness of this study. It is actually telling us that this population exists, and now we have a method to identify double quasars
that are separated by less than the size of a single galaxy." This was
a needle-in-haystack search that required the combined power of NASA's
Hubble Space Telescope and the W.M. Keck Observatories in Hawaii. Multi- wavelength observations from the International Gemini Observatory in
Hawaii, NSF's Karl G. Jansky Very Large Array in New Mexico, and NASA's
Chandra X-ray Observatory also contributed to understanding the dynamic
duo. And, ESA (European Space Agency)'s Gaia space observatory helped
identify this double quasar in the first place.

"Hubble's sensitivity and resolution provided pictures that allow us to
rule out other possibilities for what we are seeing," said Chen. Hubble
shows, unequivocally, that this is indeed a genuine pair of supermassive
black holes, rather than two images of the same quasar created by a
foreground gravitational lens. And, Hubble shows a tidal feature from
the merging of two galaxies, where gravity distorts the shape of the
galaxies forming two tails of stars.

However, Hubble's sharp resolution alone isn't good enough to go looking
for these dual light beacons. The researchers enlisted Gaia, which
launched in 2013, to pinpoint potential double-quasar candidates. Gaia
measures the positions, distances, and motions of nearby celestial
objects very precisely.

But in a novel technique, it can be used to explore the distant universe.

Gaia's huge database can be used to search for quasars that mimic the
apparent motion of nearby stars. The quasars appear as single objects
in the Gaia data because they are so close together. However, Gaia can
pick up a subtle, unexpected "jiggle" that mimics an apparent change in position of some of the quasars it observes.

In reality, the quasars aren't moving through space in any measurable way.

Instead, their jiggle could be evidence of random fluctuations of light
as each member of the quasar pair varies in brightness on timescales of
days to months, depending on their black hole's feeding schedule. This alternating brightness between the quasar pair is similar to seeing a
railroad crossing signal from a distance. As the lights on both sides of
the stationary signal alternately flash, the sign gives the illusion of "jiggling." Another challenge is that because gravity warps space like a funhouse mirror, a foreground galaxy could split the image of a distant
quasar into two, creating the illusion it was really a binary pair. The
Keck telescope was used to make sure there's no lensing galaxy in between
us and the suspected double quasar.

Because Hubble peers into the distant past, this double quasar no longer exists. Over the intervening 10 billion years, their host galaxies have
likely settled into a giant elliptical galaxy, like the ones seen in the
local universe today. And, the quasars have merged to become a gargantuan, supermassive black hole at its center. The nearby giant elliptical galaxy,
M87, has a monstrous black hole weighing 6.5 billion times the mass of
our Sun.

Perhaps this black hole was grown from one or more galaxy mergers over
the past billions of years.

The upcoming NASA Nancy Grace Roman Space Telescope, having the same
visual acuity as Hubble, is ideal for binary quasar hunting. Hubble has
been used to painstakingly take data for individual targets. But Roman's
very wide-angle infrared view of the universe is 200 times larger than Hubble's. "A lot of quasars out there could be binary systems. The Roman telescope can do huge improvements in this research area," said Liu.

* RELATED_TOPICS
o Space_&_Time
# Black_Holes # Space_Telescopes # Astronomy #
Astrophysics # Galaxies # NASA # Space_Exploration #
Cosmology
* RELATED_TERMS
o Hubble_Deep_Field o Compton_Gamma_Ray_Observatory
o Edwin_Hubble o Spitzer_space_telescope o Galaxy o
Radio_telescope o Large-scale_structure_of_the_cosmos o
Galaxy_formation_and_evolution

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


========================================================================== Related Multimedia:
*
Artist's_concept_shows_brilliant_glare_of_two_quasars_residing_in_cores
of_two_galaxies_that_are_in_the_chaotic_process_of_merging ========================================================================== Journal Reference:
1. Yu-Ching Chen, Xin Liu, Adi Foord, Yue Shen, Masamune Oguri,
Nianyi Chen,
Tiziana Di Matteo, Miguel Holgado, Hsiang-Chih Hwang, Nadia
Zakamska. A close quasar pair in a disk-disk galaxy merger at z =
2.17. Nature, 2023; 616 (7955): 45 DOI: 10.1038/s41586-023-05766-6 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/04/230405130135.htm

--- up 1 year, 5 weeks, 2 days, 10 hours, 50 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)