FLASH Talks: Haowen Zhang (Steward Observatory) & David Setton (University of Pittsburgh)

Friday, 04 November 2022 1 p.m. — 2 p.m. MST

NOIRLab Headquarters | 950 North Cherry Ave., Tucson, AZ 85719

Haowen Zhang (Steward Observatory) & David Setton (University of Pittsburgh)
Haowen Zhang, Steward Observatory
Trinity: Self-consistent dark matter halo--galaxy--supermassive black hole connection from z=0-10, and predictions on high-z quasars in the JWST era. 
We present TRINITY, a flexible empirical model that self-consistently infers the statistical connection between dark matter haloes, galaxies, and supermassive black holes (SMBHs). TRINITY is constrained by galaxy observables from 0 < z < 10 and SMBH observables from 0 < z < 6.5. The model includes full treatment of observational systematics (e.g., AGN obscuration and errors in stellar masses). From these data, TRINITY infers the average SMBH mass, SMBH accretion rate, merger rate, and Eddington ratio distribution as functions of halo mass, galaxy stellar mass, and redshift. Key findings include: 1) the normalization and the slope of the SMBH mass–bulge mass relation increases mildly from z = 0 to z = 10; 2) The apparent overmassive SMBHs at z~6 can be explained by selection bias in flux limited surveys. Trinity also predicts the quasar luminosity functions as a function of host galaxy mass and redshift, which will enable more accurate high-z galaxy property measurements in the JWST era.



David Setton, University of Pittsburgh

How Does Star Formation End: Understanding Quenching with Multi-Wavelength Studies of Massive Post-Starburst Galaxies

Understanding the process by which star forming galaxies transform to quiescence is at the forefront of studies of galaxy evolution. Evidence points to a rapid mode of quenching that dominates at high redshift, shutting off star formation on short timescales following an intense episode of star formation. In order to study the way this process transforms galaxies, I utilize statistical samples of post-starburst galaxies (PSBs) which have rapidly truncated a period of intense star formation. First, I will present work from the SQuIGGLE Survey studying a large sample of PSBs identified in the SDSS at z~0.7. I will highlight work on the age gradients, structures, and molecular gas in these galaxies which together paint a story of compact star forming progenitors which hold on to a significant amount of molecular gas after quenching. I will then present work studying the growth of the red sequence by rapid quenching using the DESI Survey Validation Luminous Red Galaxy Sample, which contains the largest spectroscopic sample of post-starburst galaxies at z>1 to date. I will showcase limits on the formation rate of massive quiescent galaxies as a function of cosmic time and preview an upcoming HST program that will place novel constraints on the sizes and structures of z>1 PSBs. Finally, I will suggest a vision for the path forward by previewing the next generation of spectroscopic surveys that will push our understanding of rapid quenching out to cosmic noon.