All colloquia are held in Mendel Hall except as noted.
Call the department office, (610)519-4820, for more information.

Date: Friday, April 25, 2008 Title: Long Term Variability in X-Ray Binaries
Speaker: Dr. Padi Boyd (VU ’87) From: Astroparticles Physics Laboratory Goddard Space Flight Center Time/Place:  Reception 3:30 pm in Mendel 455 -- Lecture 4:00 pm in Mendel 103
Date: Thursday, April 17, 2008 Title: Active Galactic Nuclei in Clusters of Galaxies
Speaker: Quyen Nguyen Hart (VU ’96) From: Center for Astrophysics & Space Science, University of Colorado at Boulder Time/Place:  Reception 4:00 pm in Mendel 455 -- Lecture 4:30 pm in Mendel 341 Clusters of galaxies are the largest gravitationally bound systems in the universe. These dense systems are unique locations to study galaxy formation and evolution. In particular, we investigate how cluster environments affect the nature of active galactic nuclei (AGN). I will present a multi-wavelength study to locate these rare cluster AGN, categorize their host galaxies, and estimate their impact on solving the “cooling flow” problem in clusters of galaxies.
Date: Friday, March 14, 2008 Title: Results on White Dwarfs, Brown Dwarfs and Extrasolar Planets
Speaker: Dr. James Liebert From: Steward Observatory, University of Arizona Time/Place:  Reception 3:30 pm in Mendel 455 -- Lecture 4:00 pm in Mendel 103
Date: Friday, February 15, 2008 Title: X-ray Properties of the First Unbiased Sample of Local AGNs
Speaker: Lisa Winter From: University of Maryland VU Class of 2003 Time/Place:  Reception 3:30 pm in Mendel 455 -- Lecture 4:00 pm in Mendel 103 The SWIFT Burst Alert Telescope (BAT), when not focused on a Gamma-ray outburst, conducts an all-sky survey in the 14-195keV band. After the first nine months, the BAT has detected a sample of 153 local (< z > = 0.03) AGN at a flux limit of a few times 10-11 erg/s/cm-2. (Tueller et & al. 2007) Since the AGN were detected at very high X-ray energies, they are an unbiased sample toward column densities below 1025 cm-2. The paper will present results from an ongoing study of the X-ray and optical properties of this AGN sample.
Date: Wednesday, December 12, 2007 Title: Resolving Complex M Supergiant Atmospheres: The Hot and the Cold of It
Speaker: Dr. Graham M. Harper From: Center for Astrophysics and Space Astronomy University of Colorado Time/Place:  Reception 4:00 pm in Mendel 455 -- Lecture 5:00 pm in Mendel 103
Date: Monday, December 3, 2007 Title: Meteorite Density and Asteroid Structure: Are Asteroids Fluffy?
Speaker: Dr. Guy Consolmagno, S. J. From: Vatican Observatory Time/Place: 4:30PM Lecture in Mendel 103 -- Reception 4:00PM in Mendel 455 Meteorite density and porosity measurements and the recent reliable determination of asteroid densities allows a comparison to the densities of the meteorites believed to come from the asteroid belt. These data are leading us to a new and sometimes surprising understanding of the environment around our infant sun and its nascent solar system. The implications range from strategies for defending Earth from rogue asteroids to the definition of Pluto and similar bodies as “dwarf planets.”
Date: Friday, November 19, 2007 Title: A Synthesis of Fundamental Issues in the formation and Early Evolution of Low-Mass Stars and Brown Dwarfs
Speaker: Dr. Keivan Stassun From: Vanderbilt University Time/Place: 5:00PM Location Mendel 103 -- Reception 4:30PM in Mendel 455
Date: Friday, November 16, 2007 Title: Dwarfs and Extrasolar Planets
Speaker: Dr. James Liebert From: Observatory, University of Arizona Time/Place: 4:00PM Location Mendel 103 -- Reception 3:30PM in Mendel 455
Date: Friday, November 9, 2007 Title: Hubble Space Telescope Observations of the Light Echo around V838 Monocerotis
Speaker: Dr. Howard Bond From: Space Telescope Science Institute Time/Place: 4:00PM Location Mendel 103 -- Reception 3:30PM in Mendel 455