Seminari
Thursday 02/12/2021 @ 11:30, JAC - Sala IV piano Battiferro (remote)
Francesco Valentino (Cosmic Dawn Center - Niels Bohr Institute - University of Copenhagen), "The properties of the interstellar medium of normal star-forming galaxies at high redshift: story of an ALMA survey"
The molecular gas is a central piece in the puzzle of galaxy evolution, being the fuel for star formation and stellar mass growth. The recent advent of powerful interferometric facilities finally unlocked the investigation of the cold gas reservoirs in "normal" galaxies on the main-sequence representing the bulk of the population in the distant Universe and not only in exceptionally starbursting or lensed objects. Here I will report on the results of an ALMA campaign systematically targeting several carbon monoxide CO and neutral atomic carbon [CI] transitions (and their underlying dust continuum emission) in order to assess the amount and the excitation properties of the molecular gas in a sample of main sequence galaxies at z=1-1.7. We find evidence that such sample differs from strongly starbursting galaxies in terms of gas excitation, [CI] abundance, CO spectral line energy distribution, and several other properties. However, we see these properties smoothly changing from one population to the other, with a significant pool of compact main-sequence galaxies showing signatures typical of starbursts. Moreover, we do not detect any strong effects of central AGN on the molecular gas reservoirs of our sample, excluding a handful of objects where the contrast between the nuclear and star formation activities is extreme, independently of the location with respect to the main sequence.