RSAA Colloquia / Seminars / Feast-of-Facts: Thursday, 07 May 2015, 11:00-12:00; Duffield Lecture Theatre

Paolo Serra

"Neutral hydrogen gas in early-type galaxies: results from the Atlas3D survey"

We often describe galaxies at z=0 as a bimodal population. On one side we have gas-rich, star-forming spirals; on the other, passively-evolving, gas-poor, early-types. The former, with their star formation activity and complex hydrodynamics, sound like much more fun than the latter -- but is this really the case? In this talk I will present results from a large survey of neutral hydrogen gas (HI) in early-type galaxies carried out as part of the Atlas3D project. I will show that early-type galaxies form a surprisingly heterogeneous family when it comes down to HI, covering four orders of magnitude in M(HI)/M(star) and a wide range of gas morphologies. I will discuss the role of environment in shaping these properties and present results on the misalignment between the angular momenta of stars and HI in these objects, as well as a comparison to hydrodynamical cosmological simulations. Future HI surveys will allow us to greatly expand this line of investigation and I will discuss this by giving a brief update on ASKAP commissioning.