Speaker
Description
Studying the multiphase circum-galactic medium (CGM) and its connection to the baryons in the host galaxies through the cosmic baryon cycle is an important step towards a better understanding of the evolution of galaxies. Large steps forward have been made in detecting the multiphase CGM through absorption line studies and connecting the CGM to its host galaxy. However, the link to the molecular gas phase from which the stars form is still missing. We have exploited ALMA calibrator observations to perform a novel (sub)mm survey, ALMACAL. We search for CO emission lines from the host galaxies of known Lyman alpha absorbers. We have detected three galaxies in multiple CO transitions indicating more excited ISMs than in normal star-forming galaxies. Furthermore, we find more evidence for intervening absorbers being connected to groups rather than isolated galaxies from our ALMA and follow-up MUSE observations.
In addition to the local baryon cycle, we also study the global baryon cycle by combining the cosmic star formation history with the evolution of $\Omega_{\rm HI}$ and $\Omega_{\rm H_2}$. By conducting a blind search for molecular absorption lines seen in the spectra of radio-bright quasars in ALMACAL, we measure the evolution of $\Omega_{\rm H_2}$. The resulting measurement of the cosmic molecular gas density will serve as an independent comparison to the results of CO emission line surveys such as ASPECS and COLDz.
| Wish list question? | 1. Just how well do we know the cosmic evolution of Omega_HI(z) and Omega_H2(z)? |
|---|
