Colloquia Schedule Fall 2015

Colloquia are on Tuesdays (unless otherwise indicated) at 3:30 pm in RLM 15.216B


Sep. 1	No Colloquium scheduled.
Sep. 8	"Convection in Cool Stars, as Revealed through Stellar Brightness Variations" abstract Fabienne Bastien Pennsylvania State University host: Adam Kraus or Bill Cochran
Sep. 15	"Compact Objects in Globular Clusters" abstract Thomas Maccarone Texas Tech host: Karl Gebhardt
Sep. 22	"Convection in Low-Mass Stellar Evolution, or 'What about magnetic fields?' " abstract Gregory Feiden University of Uppsala, Sweden host: Andrew Mann
Sep. 29	"Tracing the Cosmic Shutdown of Star Formation in Massive Galaxies" abstract Katherine Whitaker Hubble Fellow, UMass Amherst host: Steve Finkelstein
Oct. 6	"The Assembly of Disk Galaxies" abstract Susan Kassin Space Telescope Science Institute host: Rachael Livermore
Oct. 13	*"Are we Correctly Measuring Star Formation Rates?"* Integrating our knowledge of star formation (SF) traced by observations at different wavelengths is essential for correctly interpreting and comparing SF activity in a variety of systems and environments. This study compares extinction corrected integrated ultraviolet (UV) emission from resolved galaxies with color-magnitude diagram (CMD) based star formation rates (SFRs) derived from resolved stellar populations and CMD fitting techniques in 19 nearby starburst and post-starburst dwarf galaxies. The data sets are from the panchromatic Starburst Irregular Dwarf Survey and include deep legacy GALEX UV imaging, Hubble Space Telescope optical imaging, and Spitzer MIPS imaging. For the majority of the sample, the integrated near-UV fluxes predicted from the CMD-based SFRs-using four different models-agree with the measured, extinction corrected, integrated near-UV fluxes from GALEX images, but the far-UV (FUV) predicted fluxes do not. Furthermore, we find a systematic deviation between the SFRs based on integrated FUV luminosities and existing scaling relations, and the SFRs based on the resolved stellar populations. This offset is not driven by different SF timescales, variations in SFRs, UV attenuation, nor stochastic effects. This first comparison between CMD-based SFRs and an integrated FUV emission SFR indicator suggests that the most likely cause of the discrepancy is the theoretical FUV-SFR calibration from stellar evolutionary libraries and/or stellar atmospheric models. We present an empirical calibration of the FUV-based SFR relation for dwarf galaxies, with uncertainties, which is -53% larger than previous relations. close Kristen McQuinn University of Texas at Austin host: Adam Kraus
Oct. 20	No Colloquium Scheduled, to avoid conflict with: Bashfest 2015: Frank N. Bash Symposium 2015, October 18-20, 2015 Speaker: Dr. Frank N. Bash and invited speakers "New Horizons in Astronomy"
Oct. 27	Tinsley Scholar: Interstellar Group (visiting: Oct 25-31) "The Impact of Stellar Feedback on Molecular Clouds" abstract Stella Offner Affiliation: University of Massachusetts, Amherst host: Neal Evans
Nov. 3	Tinsley Scholar: Theory Group (visiting: late Oct - early Nov) "Disk Dynamos: Understanding the Origin of Galacic Magnetic Fields" abstract Ethan Vishniac Johns Hopkins University host: TBD
Nov. 10	"From TripleSpec to NEWS: Exoplanet Discovery Science with Bread and Butter Infrared Spectroscopy" abstract Philip S. Muirhead Boston University host: Adam Kraus
Nov. 17	"New Insights on Galaxy Formation from Comparisons of Simulated and Observed Galaxies" abstract Joel R. Primack UC Santa Cruz host: Paul Shapiro
Nov. 24	No colloquium scheduled.
Dec. 1	DeVaucouleurs Medalist "Expansion of the Universe Seen by Hubble" abstract Adam Riess Johns-Hopkins University, and Space Telescope Science Institute, and DeVaucouleurs Medalist host: Shardha Jogee, Chair
Dec. 8	"Supernovae and their Progenitor Systems (or lack thereof)" abstract Ori Fox Space Telescope Science Institute host: Jeff Silverman