James Webb Space Telescope Feed Post

Detection of an X-ray quasar in a gravitationally-lensed z=10.3 galaxy suggests that early supermassive black holes originate from heavy seeds

Paper abstract: Observations of high-redshift quasars reveal that many supermassive black holes (BHs) were in place less than 700 Million years after the Big Bang. However, the origin of the first BHs remains a mystery. Seeds of the first BHs are postulated to be either light (i.e., 10-100\ \rm{M_{\odot}}), remnants of the first stars or heavy (i.e., 10^4-10^5\ \rm{M_{\odot}}), originating from the direct collapse of gas clouds. Detection of growing BHs at very early times in the Universe (z>10) offers the cleanest method to probe seed origins. Harnessing recent data from the Chandra X-ray Observatory, we report the detection of an X-ray-luminous massive BH in a gravitationally-lensed galaxy identified by JWST at z~10.3 behind the cluster lens Abell 2744. Combining Chandra and JWST observations, we can now witness the growth of the very first BHs and measure the properties of their host galaxies. This heavily-obscured quasar with a bolometric luminosity of L_{\rm bol}~5\times10^{45}\ \rm{erg\ s^{-1}} harbors a M_{\rm BH}~4\times10^7 \ \rm{M_{\odot}} BH assuming accretion at the Eddington limit. This mass is comparable to the inferred stellar mass of its host galaxy, in contrast to what is found in the local Universe wherein the BH mass is ~0.1% of the host galaxy's stellar mass. The combination of such a high BH mass and large BH-to-galaxy stellar mass ratio just ~500 Myrs after the Big Bang was theoretically predicted and is consistent with a picture wherein such BHs originated from heavy seeds.