Recent Talks

Models of galaxy formation predict that gas accretion from the cosmic web is a primary driver of star formation over cosmic history. Except in very dense environments where galaxy mergers are also important, model galaxies feed from cold streams of gas from the web that penetrate their dark matter haloes. Although these predictions are unambiguous, the observational support has been indirect so far. I will report spectroscopic evidence for this process in extremely metal-poor galaxies (XMPs) of the local Universe, taking the form of localized starbursts associated with gas having low metallicity. Because gas mixes azimuthally in a rotation timescale (a few hundred Myr),  the observed metallicity inhomogeneities are only possible if the metal-poor gas producing stars fell onto the disk recently. I will analyze several possibilities for the origin of the metal-poor gas, favoring the metal-poor gas infall predicted by numerical models. In addition, I will show model galaxies in cosmological numerical simulations with starbursts of low metallicity like to the star-forming regions in XMPs.

For over 20 years, the Southeastern Association for Research in Astronomy (SARA) has operated a remotely-accessible 1-m-class telescope at the Kitt Peak National Observatory near Tucson, Arizona that has served as a focus for faculty and student research.  From its four charter institutional members, the SARA consortium has grown to include a dozen universities spanning Indiana to Florida.  In 2007, SARA assumed operations of a similar remotely-operated telescope at Cerro Tololo Interamerican Observatory in Chile.  SARA has most recently partnered with the Instituto de Astrofisica de Canarias (IAC) to automate and assume operations of the Jacobus Kapteyn Telescope (JKT) at the Roque des los Muchachos on La Palma.  This talk will provide a brief historical perspective on the SARA consortium as well as a summary of our facilities, research interests and prospects for the future.

The realism of hydrodynamical simulations of the formation and evolution of galaxies has improved considerably in recent years. I will try to give some insight into the reasons behind this success, focusing in particular on the importance of subgrid models and the associated limitations. I will also present recent results from the cosmological EAGLE simulations as well as from higher-resolution simulations of individual galaxies.