Title Opening the Era of Quasar-host Studies at High Redshift with JWST

Speaker：Xuheng Ding (丁旭恒)( Kavli IPMUs)

Time：2:00 pm Oct. 13th (Friday)

Location: Lecture Hall, 3rd floor

Abstract：

The existence of high-redshift supermassive black holes (SMBHs) – shining brightly as quasars during the first billion years of our universe – presents a conundrum in astrophysics. A broad variety of physical mechanisms have been proposed for the formation and rapid growth of these early SMBHs. Promising diagnostics are the relative properties of the black hole and its host galaxy. However, up to now, the detection of stars in quasar host galaxies has been elusive beyond z ？ 3, even with deep HST observations. In this talk, I will report the first detection of the stellar component of the host galaxies of two relatively low-luminosity quasars at z > 6 observed with JWST using NIRCam and the measurement of their stellar mass.  The black hole mass of the two quasars are calibrated using the Hbeta board line using NIRSpec. Their location in the black hole mass - stellar mass plane and the relation to the local relations will be reported in this talk. The outcomes from these results are only the beginning of the extensive scientific discoveries that will be possible through JWST surveys, such as the COSMOS-Web program at approximately redshift 6. CV：

Xuheng Ding is currently a Postdoctoral Researcher (Kavli Fellow) in IPMU, the University of Tokyo, working with Prof. John D. Silverman's research group. He obtained his Ph.D. (2012-2017) at Beijing Normal University. After that, he engaged in scientific research at Wuhan University and worked as a postdoc at UCLA with Prof. Tommaso Treu. His current research focuses on high-z quasar, galaxy evolution, strong gravitational lensing, and observational cosmology. He used HST imaging data to study 32 type-1 AGNs to reveal the coevolution of scaling correlations between supermassive black hole growth and its host galaxy at redshift z ~ 1.5. As a co-PI of JWST cycle-1 and cycle-2 program, his research group is using redshift z>6 QSOs to extend the study of the scaling relation at early Universe. More recently, he is leading a HST cycle-30 program to confirm eleven very close dual AGN candidates that have the closest separation at z>1.