The James Webb Telescope deciphers black holes in the early universe

Recent observations by the James Webb Space Telescope of two quasars from the beginning of the universe reveal important insights into the early relationship between black holes and their galaxies, mirroring the mass ratios seen in the more recent universe.

New images taken by the James Webb Space Telescope (JWST) 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. Black holes have a mass about a billion times that of the Sun, and the masses of their host galaxies are about a hundred times greater, a ratio similar to what is found in the younger universe. A powerful combination of the Subaru Telescope's wide-field survey and the James Webb Space Probe has paved a new way to study the distant universe, according to a recent 2016 study. nature.

Observations of giant black holes have attracted the attention of astronomers in recent years. The Event Horizon Telescope (EHT) has begun imaging the “shadow” of black holes at the centers of galaxies. The 2020 Novel Prize in Physics was awarded for observations of stellar motion at the heart of a galaxy. milky way. While the existence of such giant black holes is well established, no one knows their origin.

Astronomers have reported the existence of black holes with a mass of a billion solar masses during the first billion years of the universe, so how could these black holes grow to be so large when the universe was so young? Even more puzzling is that observations in the local universe show a clear relationship between the mass of supermassive black holes and the more massive galaxies in which they reside. Galaxies and black holes have completely different sizes, so which came first: black holes or galaxies? This is a “chicken or the egg” problem on a cosmic level.

3.6 µm JWST NIRCam image of HSC J2236+0032. The thumbnail image, the quasar image, and the image of the host galaxy after subtracting the quasar light (from left to right). Image scale is indicated in light years in each panel. Credit: Ding, Ono, Silverman et al.

An international team of researchers is led by Masafusa Onui, a Kavli Fellow for Astrophysics at the Kavli Institute for Astronomy and Astrophysics (KIAA) at Peking University, and Shuheng Ding, a Research Fellow at the Kavli Institute for Cosmic Physics and Mathematics (Kavli IPMU). ), and John Silverman, a Kavli professor at IPMU, set out to answer this question using James Webb Space Telescope (JWST), a 6.5-meter space telescope developed through an international collaboration between… NASAthe European Space Agency (ESA), and the Canadian Space Agency (CSA), and were launched in December 2021.

Quasars are luminous, while their host galaxies are faint, which has made it difficult for researchers to detect faint galactic light in the quasar's glow, especially at long distances. “Finding the host galaxies of quasars at redshift 6 is like trying to spot fireflies in a spectacular fireworks show while wearing fogged glasses. The host galaxies are incredibly faint, and the image resolution was very limited, even with Hubble Space Telescope“Which makes revealing its hidden beauty a real challenge,” says Xuheng Ding.

Artist's concept of NASA's James Webb Space Telescope. Image source: NASA, ESA, and Northrop Grumman

The team observed two quasars with the James Webb Space Telescope, HSC J2236+0032 and HSC J2255+0251, at redshifts of 6.40 and 6.34 when the universe was about 860 million years old. These two quasars were originally discovered through a large-scale survey of the 8.2-meter Subaru telescope, with which the research team has identified more than 160 quasars to date. The relatively low luminosities of these quasars make them prime targets for measuring the properties of their host galaxy, and the successful discovery of the hosts represents the first epoch to date in which starlight has been detected in a quasar.

Images of quasars at infrared wavelengths of 3.56 and 1.50 microns were captured using JWST's NIRCam instrument, and host galaxies became apparent after careful modeling and subtraction of the glow from accreting black holes. The host galaxy's stellar signature was also seen in the spectrum captured by JWST's NIRSpec of J2236+0032, supporting the discovery of the host galaxy. “I have been deeply involved in Subaru's survey of high-redshift quasars since my doctoral years at the National Astronomical Observatory of Japan. I am extremely proud of the successful detection of starlight from HSC quasars that we found with Subaru,” says Masafusa Onoe.

Kavli IPMU project researcher Xuheng Ding, Professor John Silverman, and Kavli Institute for Astronomy and Astrophysics (PKU-KIAA) Kavli Astrophysics Fellow Masafusa Onoue (from left). Source: Kavli IPMU, Kavli IPMU, Masafusa Onoue

Through observations, the team found that… Black hole The host galaxy's mass is similar to that seen in the younger universe. The result suggests that the relationship between black holes and their hosts already existed during the first billion years after the explosion the great explosion. The team will continue this study with a larger sample of distant quasars, with the goal of constraining the co-evolutionary growth history of black holes and their parent galaxies over cosmic time. These observations will constrain models of the co-evolution of black holes and their host galaxies.

Read more about this discovery at Researchers Discover Quasar Host Galaxies in the Early Universe.

Reference: “Detecting stellar light from quasar host galaxies at redshifts higher than 6” by Shuheng Ding, Masafusa Onui, John D. Silverman, Yoshiki Matsuoka, Takuma Izumi, Michael A. Strauss, Knud Janke, Camryn L. Phillips, Junyao Li, Marta Voluntieri, Zoltan Heymann, Erham Tawfik Andika, Kentaro Aoki, Shunsuke Baba, Rebecca Perry, Sarah E. Bosman, Connor Bottrell, Anna-Kristina Ehlers, Seiji Fujimoto, Melanie Haposet, Masatoshi Imanishi, Kohei Inayoshi, Kazushi Iwasawa, Nobunari Kishikawa, Toshihiro. Kawaguchi, Kotaro Kohno, Shin-Hsiu Lee, Alessandro Lupi, Jianwei Liu, Toru Nagao, Roderick Overzer, Jan Törg Schindler, Malte Schramm, Kazuhiro Shimasako, Yoshiki Toba, Benny Trachtenbrot, Maxim Trebich, Tommaso Trieu, Hideki Umehata, Bram B. Vennemans, Marianne Vestergaard, Fabian Walter, Feig Wang, and Jenny Yang, June 28, 2023, nature.
doi: 10.1038/s41586-023-06345-5