Abstract: The detections of bright dust continuum, molecular CO, and [CII] 158 micron line in the host galaxies of the luminous quasars at the highest redshift reveal massive star formation in the nuclear region of the young quasar hosts. We carried out a series of observations with ALMA, NOEMA, and the VLA, to probe the dust continuum, molecular CO, and fine structure line emission from the quasar-starburst systems at z~6. These observations allow a full study of the star formation, gas excitation, and gas kinematics in the quasar host galaxies, which are the keys to understand the early growth of these quasar-galaxy systems. In this talk, I will review our recent studies on the kinematics and excitation of the molecular and atomic interstellar medium (ISM) in the central a few kpc region of the quasar host galaxies at z~6. The gas distribution and velocity field provide preliminary estimates of the host dynamical masses, which constrains the black hole - galaxy mass relation in the early universe. The line ratios constrain the range of gas density, temperature, as well as the strength of the radiation field in the nuclear region. We discuss the contributions from AGN and star formation to the heating and excitation of the ISM in these young quasar host galaxies.
Bio: Ran Wang is working on millimeter and radio studies of the co-evolution between supermassive black holes and their host galaxies in the early universe. She earned her Bachelor's degree and Ph.D. at Peking University in 2004 and 2009, respectively. Then she was awarded the Jansky fellowship of the national radio astronomical observatory (NRAO). After the postdoc research at the University of Arizona, she joined the faculty at Peking University in 2013. She has developed a series of observational programs to search and map the dust and gas components in the host galaxies of quasars discovered at z∼6, using the large millimeter and centimeter telescopes, such as ALMA, VLA, JCMT, and NOEMA.