Presentation #343.10 in the session Potpourri of Galaxies — iPoster Session.
The Triangulum galaxy (M33) is one of the spiral galaxies in the Local Group. It is smaller and less massive than the other two members of the Local Group, the Andromeda and Milky Way galaxies. M33 is a spiral galaxy at a distance of about 859 kpc. Given its proximity to the Milky Way, M33 plays an important role in our understanding of the formation and evolution of relatively low mass spiral galaxies. In this third poster of a series of three AAS posters, we present a study of the rotational kinematics of M33’s ionized gas disk. The study uses the Deep Imaging Multi-Object Spectrograph (DEIMOS) spectroscopic data from the TREX survey — specifically serendipitously detected emission lines associated with the ionized phase of M33’s interstellar medium. As explained in the first poster of this series, we have carried out optimal subtraction of the atmospheric airglow emission lines from these sky spectra. In this the third of a series of three AAS posters, we present a map of the line-of-sight velocity of M33’s ionized gas disk. We compare the kinematic of M33’s ionized gas disk to the kinematics of the neutral atomic hydrogen gas (HI) disk, molecular gas disk (as traced by CO), and stellar disk. The rotation curves derived from these data provide constraints on M33’s dark matter halo: its total mass and radial density profile. Asymmetries in the rotational curve may be related to the interaction history of M33.
This research was supported in part by the NSF and NASA/STScI. This research was conducted under the auspices of the Science Internship Program (SIP) at the UC Santa Cruz. We wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to work with observations from this mountain.