Gas and Star Formation in M33: An Artistic Pathway

Abstract

M33 is the closest blue, star forming, flocculent spiral galaxy for which it has been possible to combine an overwhelming quantity of multiwavelength high resolution data to shed light on its assembly and star formation across cosmic time. I will summarize some of the key ingredients related to the formation and evolution of this galaxy, such as its dark matter, the baryonic distribution and the metallicity gradients. M33 is a pure disk galaxy with a lower baryonic fraction than M31, of order 0.02, and a dark matter profile typical of structure growth in ΛCDM cosmology. Disk dynamics and the growth of perturbations can be visualized in a detailed 2-D map. The consequent star forming sites across the disk, analyzed using mid-infrared observations, points out young stellar clusters spanning 4 orders of magnitude in luminosity. This database has allowed to study IMF sampling at the high mass end and the concept of a cluster birthline. Stars and gas, present beyond 2-optical radii, point out to the occurrence of possible cosmic gas infall fueling star formation. Bruce Elmegreen’s outstanding contribution to science becomes evident in the analysis of M33, here underlined also through an artistic pathway.