May 7, Tuesday 1:10 pm
Speaker: Eric Bell, Michigan
Location: Hearst Field Annex, B1 (also videoconferenced to 50-5026)
Title: “The effects and importance of galaxy merging in a cosmological context”
Abstract: Mergers between dark matter halos, and the galaxies in them, are a central feature of Lambda CDM. In this talk, I explore the role of galaxy merging in setting the properties of galaxies, in particular the properties of non-star forming (quiescent) early-type galaxies. I will discuss a number of relevant considerations : the observation that the best structural predictor of quiescence is light profile shape (i.e., relative size of the bulge); the comparison between inferred merger rates and the rate of creation of early-type galaxies; the effect of merging on setting the scaling relations of present-day early-type galaxies, and the result that < ~10% of cosmic-averaged star formation is directly triggered by mergers. I will argue that mergers are a crucial part of how early-type galaxies come into place. I will conclude with a number of potentially important open issues: the frequent existence of disks and/or rotation in early-type galaxies, controversies about the amount of evolution in stellar mass and size in the most massive early-type galaxies, the ever-open issue of the feedback mechanism that actually keeps cold gas out of galaxies, and thoughts about the importance of galaxy merging at small galaxy masses.
This will be the last BCCP seminar of the academic year. Please check back for future seminars. Have a good summer !
For future BCCP talks, see this page.