Galactic Center gas clouds and novel bounds on ultralight dark photon, vector portal, strongly interacting, composite, and super-heavy dark matter

Cold gas clouds recently discovered hundreds of parsecs from the center of the Milky Way Galaxy have the potential to detect dark matter. With a detailed treatment of gas cloud microphysical interactions, we determine Galactic Center gas cloud temperatures, unbound electron abundances, atomic ionization fractions, heating rates, and cooling rates and find how these quantities vary with metallicity. Considering a number of different dark sector heating mechanisms, we set new bounds on ultralight dark photon dark matter for masses 10^-22-10^-10 eV, vector portal dark matter coupled through a sub--mega electron volt mass boson, and up to 10⁶⁰ GeV mass dark matter that interacts with baryons.