报告题目：Studying Quasar-host Galaxy Evolution at Redshift 6 with Large Millimeter and Radio Interferometer Arrays

报 告 人：王然，亚利桑那大学

报告摘要：Observations of high-redshift quasars probe the growth of supermassive black holes (SMBH) and their connections to galaxy formation at the earliest epoch. Large samples of quasars have been discovered at z~6. We have been carrying out a systematic survey of the star formation and ISM properties in the host galaxies of z~6 quasars using millimeter dust continuum and molecular CO emission. The results suggest massive star formation at rates of a few hundred to 1000 Msun/yr in ~30% of these z~6 quasars. Molecular CO line emission has been detected in 12 z~6 quasars and the CO (2-1) line emission from one of the z~6 quasars is resolved into two distinct peaks, suggesting a possible gas-rich, major merging system. We have an ALMA Cycle 0 project to search for [C II] line emission from a sample of five FIR-luminous quasars at z~6. We have data in hand for three of them and all are strongly detected. The line velocity maps of two of them show tantalizing hints of velocity gradients which may suggest emission from a rotating starburst disk; the third object shows a broader [C II] line compare to previous CO observations. High S/N and resolution observations are required to confirm and fully understand these intriguing trends. We are investigating the evolutionary properties of these dust/CO/[C II]-detected quasars at z~6. It is likely that we are seeing an early phase of SMBH-galaxy evolution, in which active bulge building is ongoing coeval with rapid SMBH accretion and the median black hole-bulge mass ratio estimated with the CO line emission is about an order of magnitude higher than the present-day value.

报告时间：8月17日，上午10：00

报告地点：紫台619会议室

联 系 人：马红君 83332210

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