A team of international scientists has successfully captured images of starlight emanating from two enormous galaxies hosting actively growing black holes, known as quasars, that existed less than a billion years after the Big Bang.
This groundbreaking feat marks the earliest epoch to date in which starlight has been detected surrounding a quasar. The black holes in question have masses nearing a billion times that of our Sun, and the ratio of their mass to the mass of their host galaxies is consistent with those observed in the more recent universe.
Initially identified during a comprehensive survey conducted by the Subaru Telescope on Maunakea, the James Webb Space Telescope (JWST) subsequently imaged these two quasars.
According to Science Alert, this research was led by astrophysicists Xuheng Ding and John Silverman of the Kavli Institute for the Physics and Mathematics of the Universe in Japan and Masafusa Onoue of the Kavli Institute for Astronomy and Astrophysics in China.
NASA's James Webb Space Telescope Captures Deep Cosmic Images
This combination of ground-based observations from the Subaru Telescope and space-based observations from the JWST has opened up new avenues for studying the remote cosmos.
The groundbreaking achievement was made possible by the JWST's remarkable capacity to capture deep images, which allowed the researchers to isolate the light from the quasar and uncover the host galaxy.
Previous observations of quasars from this era were hindered by their overwhelming brightness, rendering it impossible to separate their light from that of their host galaxies. However, by leveraging the JWST's capabilities, scientists were able to examine host galaxies from this early cosmic epoch.
Examining the early universe's host galaxies and black holes provides scientists with insights into their formation and interrelationships. Detecting the faint light emitted by galaxies amidst the glare of luminous quasars has been an arduous task, particularly over vast distances.
Before the JWST, the Hubble Space Telescope could only detect host galaxies of luminous quasars when the universe was under 3 billion years old, with no observations of younger galaxies.
The JWST's exceptional sensitivity and ability to capture ultra-sharp infrared images had finally enabled researchers to delve into the time when quasars and galaxies first emerged.
A few months after commencing regular operations, the team employed the JWST to observe two quasars: HSC J2236+0032 and HSC J2255+0251, with redshifts of 6.40 and 6.34, respectively.
The researchers utilized the JWST's NIRCam instrument to capture images of the two quasars at infrared wavelengths of 3.56 and 1.50 microns. The host galaxies were unveiled by meticulously modeling and subtracting the glare originating from the accreting black holes.
In the case of J2236+0032, the stellar signature of the host galaxy was also observed in a spectrum taken by the JWST's NIRSPEC, further substantiating the detection.
More Massive Than the Sun
Photometric analyses indicated that both quasar host galaxies were immense, measuring 130 and 34 billion times the mass of the Sun, respectively.
Moreover, measurements of the velocity of the turbulent gas in the vicinity of the quasars, derived from NIRSPEC spectra, suggested that the black holes powering them were also colossal, with masses of 1.4 and 0.2 billion times that of the Sun.
The ratio of black hole mass to host galaxy mass observed in these ancient quasars closely resembles that of galaxies in the more recent universe, implying that the relationship between black holes and their host galaxies was established as early as 860 million years after the Big Bang.
With scheduled observations planned for Cycle 1 of the JWST, the team of astronomers is eager to delve deeper into their study, which will contribute to refining models regarding the coevolution of black holes and their host galaxies.
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