报告摘要：First-year JWST observations have demonstrated its capability to achieve what was previously impossible with the Hubble Space Telescope. One of the highlights includes the detection of stellar emission from quasar host galaxies at high redshift, thanks to the telescope’s high infrared sensitivity as well as its stable and sharp point spread function. This presentation will provide some of the latest results from our JWST follow-up observations of z=6 quasars discovered by a Subaru Telescope’s optical wide-field survey. These intermediate-luminosity quasars have proven to be the best targets for studying quasar hosts, thanks to the relatively low contrast of the quasar emission. We are now compiling the first sample of secure measurements of host stellar masses and central black hole masses, which we aim to use to address the cosmic-scale “chicken-or-egg” problem: 'Do black holes form first?' or 'How does the local scaling relation evolve from z > 6 to the present day?' Two of our Cycle 1 targets also show intriguing stellar absorption line features in their NIRSpec rest-frame optical data. These post-starburst galaxies hosting active black holes are in clear contrast to luminous quasars hosted by starburst galaxies. I will conclude by presenting our strategy for future JWST cycles.

主讲人简介：Masafusa Onoue is an expert of observations of high-redshift quasars based on ground-based telescopes and JWST. He has been awarded multiple JWST GO programs as PIs. He received his PhD degree in 2018 from SOKENDAI, Japan, under supervision of Prof. Nobunari Kashikawa at National Astronomical Observatory of Japan. He then moved to Max Planck Institute for Astronomy as a postdoc in the group of Fabian Walter, and joined KIAA as a Kavli Astrophysics Fellow from December 2021. He has been continuing his Kavli Fellowship in Kavli IPMU since November 2023.