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"


Fabienne Bastien

Pennsylvania State University

host: Adam Kraus or Bill Cochran

Sep. 15

"Compact Objects in Globular Clusters"


Thomas Maccarone

Texas Tech

host: Karl Gebhardt

Sep. 22

"Convection in Low-Mass Stellar Evolution, or 'What about magnetic fields?' "


Gregory Feiden

University of Uppsala, Sweden

host: Andrew Mann

Sep. 29

"Tracing the Cosmic Shutdown of Star Formation in Massive Galaxies"


Katherine Whitaker

Hubble Fellow, UMass Amherst

host: Steve Finkelstein

Oct. 6

"The Assembly of Disk Galaxies"


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.


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"


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"


Ethan Vishniac

Johns Hopkins University

host: TBD

Nov. 10

"From TripleSpec to NEWS: Exoplanet Discovery Science with Bread and Butter Infrared Spectroscopy"


Philip S. Muirhead

Boston University

host: Adam Kraus

Nov. 17

"New Insights on Galaxy Formation from Comparisons of Simulated and Observed Galaxies"


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"


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)"


Ori Fox

Space Telescope Science Institute

host: Jeff Silverman

Visitors to the Department of Astronomy can find detailed information and maps on our Visiting Austin Page.

Please report omissions/corrections to: G. Orris at

23 November 2015
Astronomy Program · The University of Texas at Austin
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