Lunch talk on Oct. 24, 2022

Cosmic Evolution of Star Formation, Cold Molecular Gas and Dark Matter in Galaxies

Speaker: Daizhong Liu (MPE)

Venue: Video Conference

Time: 12:30 PM, Monday, Oct. 24, 2022

Abstract: 

It is established that galaxies have undergone rapid evolution over more than ten billion years of cosmic time. Surveys of high-redshift galaxies in deep fields with world-class multi-wavelength observing facilities (e.g., Hubble, Spitzer and Herschel Space Telescopes, and the ALMA interferometer) have led to great advances in our knowledge of galaxy stellar mass assembly and star formation evolution, and recently the cold molecular gas and dark matter fraction in galaxies. In this talk, I will present our studies of the cosmic star formation rate and cold molecular gas densities, and dark matter fractions, using thousands of high-redshift galaxies up to redshift z~6 within the GOODS and COSMOS deep fields. We developed photometric + spectral energy distribution (SED) super-deblending technique to exploit the Herschel surveys in these deep fields, and developed an automatic mining system (A3COSMOS) to exploit the public ALMA (sub-)mm science archive. These gave us the largest sample of dusty star-forming galaxies with which we can trace the obscured cosmic star formation rate density and cold molecular gas density out to z~6. In addition, with deep integral field unit (IFU) observations and cutting-edge 3D forward kinematic modeling, we further constrained for the first time the dark matter fractions for one hundred massive galaxies in the Cosmic Noon (z~1-2). These results build up the precise descriptions of galaxy evolution across cosmic time, critical to theories and cosmological simulations. Finally, I will present an outlook on the near future of galaxy evolution, where with deep and wide JWST surveys (e.g., the largest JWST Cycle 1 program, COSMOS-Web) and ALMA/NOEMA/JVLA/MeerKAT surveys we will unveil the mysterious, very early Universe (z>6).

Report PPT:  SWIFAR_Daizhong Liu.pdf