Webb Telescope Captures Images of Quasar Host Galaxies in Early Universe
June 28, 2023 - In a groundbreaking discovery, scientists utilizing the James Webb Space Telescope (JWST) have successfully captured images of starlight from two massive galaxies hosting actively growing black holes, known as quasars. These images reveal the earliest epoch to date in which light from stars has been detected around a quasar, less than a billion years after the Big Bang. The findings shed light on the formation of black holes and their relationship with host galaxies in the early universe.
The Study and Findings:
Led by researchers from the Kavli Institute for the Physics and Mathematics of the Universe and the Peking University Kavli Institute for Astronomy and Astrophysics, the study utilized a combination of ground-based observations from the Subaru Telescope and space-based observations from the JWST. The team focused on two quasars, HSC J2236+0032 and HSC J2255+0251, which were discovered through Subaru Telescope's deep survey program. These quasars, located when the universe was around 860 million years old, provided an opportunity to study the properties of their host galaxies.
The images of the quasars were captured using JWST's NIRCam instrument, which operates at infrared wavelengths. By carefully modeling and subtracting the quasar's light, the host galaxies became apparent. In addition, the team used JWST's NIRSPEC to obtain a spectrum of one of the quasars, further supporting the detection of the host galaxy.
Implications of the Discovery:
Studying host galaxies and black holes in the early universe provides valuable insights into their formation and interdependence. Previous observations with the Hubble Space Telescope could detect host galaxies of luminous quasars when the universe was around 3 billion years old, but no younger. With the remarkable sensitivity and sharp images of JWST in infrared wavelengths, scientists can now extend these studies to the time when quasars and galaxies first emerged.
The study revealed that the quasar host galaxies were massive, measuring 130 and 34 billion times the mass of the Sun, respectively. The black holes powering these quasars were also found to be massive, with masses approximately a billion times that of the Sun. Interestingly, the ratio of black hole mass to host galaxy mass in these early quasar host galaxies mirrors that of galaxies in the more recent universe, suggesting a pre-established relationship between black holes and their hosts as early as 860 million years after the Big Bang.
Future Research and Collaboration:
The success of this study highlights the power of combining ground-based and space-based telescopes. Moving forward, the team plans to continue their research using JWST's scheduled Cycle 1 observations. They aim to identify similar targets using the MOSFIRE instrument at W. M. Keck Observatory, further expanding the sample of ancient galaxies hosting quasars in the early universe.
This remarkable discovery opens up new avenues for understanding the early universe and the intricate relationship between black holes and their host galaxies. With the JWST's capabilities and collaborative efforts, scientists are poised to uncover more secrets of our cosmic origins.