GBT26B-315

Mapping cold neutral hydrogen in metal selected galaxies

Abstract

The study of gas flows in and around galaxies is key to understanding the processes of formation, gas accretion, and metal enrichment in the circum-galactic and intergalactic medium. We propose 20.75 hours of GBT observations targeting five strong MgII/FeII absorbers with equivalent widths greater than 1 angstrom, likely tracing the dense cold phase of the interstellar medium at average redshifts of ~0.8. The absorber host galaxies are located at small impact parameters (< 20 kpc), as identified from deep multi-band imaging surveys conducted using the 8m HSC-Subaru and 4m DESI telescopes, and host compact radio-loud quasars in the background, with peak flux densities exceeding 100 mJy/beam. With 20.75 hours of GBT observations, we aim to investigate the cold neutral medium, study the kinematics of neutral gas in galactic disks, and constrain its covering factor within an impact parameter of ~20 kpc. This pilot survey will assess the detectability of the 21-cm signal by integrating previously established complementary techniques for studying cold gas around galaxies through optical/UV absorption-selected samples and quasar-galaxy pairs.

Investigators

Name	Institution
Reena Chaudhary *	Indian Institute of Astrophysics
RAVI JOSHI	Indian Institute of Astrophysics
Sarbeswar Das	Indian Institute of Astrophysics
Labanya Guha	Indian Institute of Astrophysics
Michele Fumagalli	Milano-Bicocca, Università degli Studi di
Celine Peroux	European Southern Observatory

* indicates the PI