Tsukuba Uchu Forum

141st Uchu Forum

Cloud-scale molecular gas properties of nearby spiral and starburst galaxies with ALMA

Toshiki Saito

National Astronomical Observatory of Japan

(Ultra)luminous infrared galaxies (= (U)LIRGs) at z=0 form stars 10-100 times more efficiently than z=0 main sequence (MS) galaxies, which is explained by nearby (U)LIRGs being gas-rich merging galaxies. Numerical simulations and sub-kpc observations clearly show that tidal interaction between gas-rich progenitors is condensing gas and triggering subsequent starburst activity in the nuclear region and throughout the extended disk. However, it remains unclear if the properties of their GMCs, as the sites for star formation, themselves differ as well from those in normally star-forming galaxies. Obvious differences would potentially imply important changes to current theories. Before ALMA it was impossible to study GMCs in (U)LIRGs. This talk presents short-spacing corrected 40-150 pc resolution CO(2-1) data for 33 nearby (U)LIRGs, and compares basic statistical GMC properties between nearby (U)LIRGs and nearby main sequence galaxies from the PHANGS-ALMA large program. If I have time, I will talk about the other side of galaxy evolution, i.e., observational evidence for star formation quenching through AGN feedback. Image