SHAO Astrophysics Colloquium

Title: New frontiers in galaxy and cluster formation in the early universe and challenges to theoretical models
Speaker: Dr. Tao Wang (University of Tokyo/NAOJ)
Time: 3 pm, May 28(Tuesday)
Location: Lecture Hall, 3rd floor

Abstract: Our current understanding of galaxy and structure formation (both observations and theoretical modeling) in the early universe is mainly based on galaxies selected in the ultraviolet (UV), e.g., Lyman-break galaxies.  However, it is known that such UV-selected galaxies are biased significantly against massive, dusty galaxies, and it remains unclear what is the true abundance of galaxies and cosmic star formation density in the early universe. In this talk, I will present some new perspectives on these issues, enabled by recent Herschel and ALMA observations of high-redshift galaxies, which shed lights on both galaxy and large-scale structure formation in the early universe. I will further discuss  how these new discoveries challenge current galaxy formation models.

Title: Probing Astrophysics of Galactic Feedback in Nearby Disk Galaxies
Speaker: Q. Daniel Wang (University of Massachusetts/T.D Lee Institute/Shanghai Jiao Tong University) 
Time: 3 pm, May 30 (Thursday)

Location: Large Conference room, 3rd floor

Abstract: Disk galaxies are evolving ecosystems, believed to be largely regulated by feedback from massive stars and from occasional active galactic nuclei (AGN). We have been conducting multi-wavelength studies of nearby disk galaxies to test our understanding of such feedback. I will discuss how the feedback effect may be traced by galaxy-wide diffuse X-ray and radio emissions, as well as present examples of spatially resolved analyses of the relationship between diffuse hot plasma and feedback sources within individual galaxies. These studies show rich astrophysical phenomena and processes (such as charge exchange and non-equilibrium ionization evolution of AGN relics) important for understanding the working of the feedback.