IPAC Visiting Graduate Fellowship Talks - Aditya Togi - H2 rotational lines – A direct tracer for total molecular gas mass in galaxies

Robust knowledge of the molecular hydrogen (H2) gas distribution is necessary to understand star formation in galaxies. The molecular gas content must be inferred using indirect tracers like CO, dust emission, etc since H2 is not directly observable in the cold interstellar medium (ISM). We have devised a new power law model using mid infrared (MIR) rotational lines of H2 to calculate the total molecular gas mass in galaxies. We apply our model in low metallicity galaxies to recover the CO-dark molecular gas. We also use our model in starbursting (U)/LIRGs from the GOALS sample to calculate molecular gas mass in these merger systems. The molecular gas properties and their correlation with other MIR features like PAHs, dust temperature, etc will be discussed. Finally I will conclude my talk by determining the variation of CO conversion factor in these merger systems.