Molecular Gas Properties in the Host Galaxies of Fast Radio Bursts

ABSTRACT :
Fast radio bursts (FRBs) are bright, energetic radio pulses from microseconds to milliseconds. Since the discovery in 2007, thousands of FRBs have been detected; however, their physical mechanism and progenitors are still unknown. To study the galaxy environments producing FRB progenitors, we conducted CO observations of their host galaxies. Eight new host galaxies were observed with ALMA, allowing us to make a sample of more than 10 host galaxies with molecular gas observations. We found diversity in molecular gas properties (gas mass, gas depletion time, and gas fraction to stellar mass) in the sample. Our findings suggest that FRBs arise from multiple progenitors or single progenitors that can exist in a wide range of galaxy environments.