GBT22A-325

Understanding diverse HI depletion times in MaNGA star forming galaxies

Abstract

The z=0 star-forming galaxy population shows large variations in neutral atomic hydrogen (HI) depletion times, from <1 Gyr to 10s of Gyr. Significant evidence exists to suggest much of this variation is due to differences in the mean ISM properties within star-forming disks (e.g., ionization, internal motions, mean density). However, it is unclear whether longer HI depletion times are driven by inefficient molecular cloud formation or inefficient star formation within molecular clouds. We propose 81.7 hours of GBT/ARGUS time to conduct new observations of CO(1-0) and CH3OH for 89 star-forming galaxies in the SDSS-IV MaNGA survey. The CO observations will quantify molecular gas content, allowing us to determine the efficiency of molecular cloud formation and star formation directly. Observations of the shock-sensitive CH3OH will determine whether the long HI depletion times are caused by energy injected into the ISM from shock-heating, as potentially implied by enhanced [OI]6300/Halpha line ratios in galaxies with large HI depletion times. The proposed data and analysis will provide important insight into the global properties of galaxies that affect their ability to grow over cosmic time.

Investigators

Name	Institution
David Stark *	Space Telescope Science Institute; Haverford College
Kate Rowlands	Johns Hopkins University; Space Telescope Science Institute
Yuanze Luo	Johns Hopkins University
Rogerio Riffel	Rio Grande do Sul, Universidade Federal do
Zheng Zheng	National Astronomical Observatories, CAS
Justin Otter	Johns Hopkins University
Yinghui Zheng	National Astronomical Observatories, CAS
Karen Masters	Haverford College
Nicholas Boardman	Utah, University of
Vladimir Avila-Reese	México, Universidad Nacional Autónoma de

* indicates the PI