Code of Conduct
Sowgat Muzahid (AIP)
The circumgalactic medium (CGM)-- a dynamic, complex, multiphase reservoir of gas and metals surrounding galaxies-- has been recognized as an important part of galaxy ecosystems. Studying the CGM is crucial for: (i) understanding how galaxies interact with their surroundings (inflow/outflow processes) (ii) the baryon budget of galaxy halos, and (iii) constraining galaxy evolution models. To this end, we are conducting two major surveys on the CGM using ~120 hours of MUSE GTO observations. Our high-z (z>3) sample comprises ~100 Lyman alpha emitters and the low-z (z<1) sample comprises ~300 low-mass, star-forming galaxies. We use high S/N spectra of background quasars, obtained with the VLT/UVES (for high-z) and HST/COS (for low-z), to study the CGM of these galaxies using absorption line spectroscopy. In the talk, I will present an overview of survey design, and initial results of our high-z CGM survey. In particular, I will show that the stacked CGM absorption profiles can be used to calibrate Lyman-alpha redshifts which are known to suffer from resonant scattering (2019arXiv191003593M). Besides, I will present the following: (1) the radial profiles of gas and metals out to several virial radii around these low-mass galaxies, (2) possible redshift evolution of the CGM, (3) the dependence of the CGM absorption properties on the mass, star-formation rate, and environment of the galaxies.
