Date: Tue 14-Feb-2006
Speaker: D.J. Pisano (NRL)
Title: "Constraining the Nature and Evolution of Luminous Compact Blue Galaxies"
Luminous Compact Blue Galaxies (LCBGs) are blue, high surface brightness, vigorously starbursting, approximately L* galaxies. They undergo strong evolution as they are common at z~1, where they contribute about 45% of the star formation in the Universe, while they are at least 10 times rarer today. LCBGs are a morphologically and spectroscopically diverse group of galaxies. We understand little about their physical characteristics and possible evolutionary paths. I report on a large, multi-wavelength survey of the uncommon, nearby LCBGs analogous to the common, distant LCBGs to better understand the properties of this class of galaxies. I will focus mainly on the radio observations of HI in these galaxies, but will also discuss CO and optical data and their role in deciphering the current nature and future evolution of LCBGs.
Date: Thu 23-Feb-2006
Speaker: Kartik Sheth (SSC)
Title: TBD
Date: Tue 28-Feb-2006
Speaker: Roelof de Jong (STScI)
Title: Comparing dynamical and stellar population mass-to-light ratios
Deriving dark matter mass models of spiral galaxies from observed rotation curves has been hampered by the ill constrained contribution of the stellar mass component to the rotation curves. I investigate avenues to constrain the mass-to-light ratios of the stellar components in galaxies. I will pay particular interest to the relations between dynamical mass estimates of stellar systems and their mass estimate derived from stellar population synthesis codes. I then continue on to use stellar populations to calculate luminous matter distributions for a large sample with high quality rotation curves, derive their dark matter distributions, and investigate scaling relations between the dark and luminous components.
Date: Fri 24-Mar-2006
Speaker: Mark Swain
Title: "An Antarctic Infrared Interferometer"
Date: Tue 28-Mar-2006
Speaker: Ron Allen (STScI)
Title: "Photodissociation and the Morphology of HI in Galaxies"
Young massive stars produce Far-UV photons which dissociate the molecular gas on the surfaces of their parent molecular clouds. Of the many dissociation products which result from this ``back-reaction'', atomic hydrogen \HI\ is one of the easiest to observe through its radio 21-cm hyperfine line emission. In this paper I first review the physics of this process and describe a simplified model which has been developed to permit an approximate computation of the column density of photodissociated \HI\ which appears on the surfaces of molecular clouds. I then review several features of the \HI\ morphology of galaxies on a variety of length scales and describe how photodissociation might account for some of these observations. Finally, I discuss several consequences which follow if this view of the origin of HI in galaxies continues to be successful.
Date: Tue 04-Apr-2006
Speaker: Kristine Spekkens (U of Rutgers)
Title: Cold Dark Matter and the Kinematics of Massive Spirals
While many dynamical studies of spirals in the context of the Cold Dark Matter (CDM) paradigm have focussed on low mass and low surface brightness systems, insight into the structure and formation of disk galaxies can also be gleaned from the high mass extreme of the local population. I will present a sample of 8 massive, late-type systems with high-quality I-band photometry as well as HI and optical kinematics. I will examine the outer rotation curve shapes for this "fast rotator" sample, estimate their baryon angular momentum distributions and spin parameters for a wide range of mass-to-light ratios, and compare them to expectations from simulations of angular momentum growth in CDM halos.
Date: Mon 24-Apr-2006
Speaker: Sean Andrews (U of Hawaii)
Title: A Submillimeter View of Protoplanetary Disks
We present some early results from our (sub-)millimeter aperture synthesis imaging survey of protoplanetary disks using the Smithsonian Submillimeter Array on Mauna Kea. We use simultaneous fits to the spectral energy distributions and spatially resolved (sub-)millimeter continuum emission to constrain disk structure properties including surface density profiles and outer radii. Combined with a large multiwavelength single-dish survey of similar disks, we show how the observations provide evidence for significant grain growth and rapid evolution in the outer regions of disks, perhaps due to a photoevaporation process. Some prospects for improved constraints with current and future interferometers will also be discussed.
Date: Tue 02-May-2006
Speaker: Crystal Brogan
Title: Recent results from SMA observations of High Mass Star Formation
Date: Tue 16-Jan-2007
Speaker: Melvin Hoare (University of Leeds)
Title: CORNISH - A VLA Survey of the Inner Galactic Plane
Date: Thursday 15-Feb-2007
Speaker: Dr. Erik Rosolowsky (CfA)
Title: "Connecting Local and Global Star Formation"
Galaxies can be thought of as machines that turn gas into stars. Some galaxies are much more efficient at the star formation process than others, but why is this so? Molecular clouds must lie at the root of this question since all contemporary star formation occurs within these clouds. In galaxies that are efficient star-formers, are the molecular clouds substantially different from those seen in the solar neighborhood or, rather, does the enhanced star formation efficiency result from a more effective molecular cloud formation process? In this talk, I will present recent observational results that address this question. I will discuss recent studies of Giant Molecular Clouds (GMCs) in the Magellanic Clouds, M31 and M33. Using a uniform analysis method for CO surveys, I will show how the GMCs vary among and within these Local Group galaxies. Then, using these properties from the (relatively) molecule-poor regions of the Local Group as a reference, I will discuss the properties of GMCs in the molecule-rich environments that are invariably associated with starburst activity (a high star formation efficiency). On a final note, I will suggest that the pressure in the galactic ISM is an important factor in establishing GMC properties and discuss the role of ISM pressure in regulating galaxy-scale star formation.
Date: Thursday, 19-April-2007
Speaker: Prof. Jason Glenn (University of Colorado)
Title: Submillimeter Observations of the Early Universe
Date: Friday, 20-April-2007
Speaker: Dr. Rick Perley (NRAO)
Title: The Expanded VLA Project
Date: Tue 12-Jun-2007
Speaker: Dr. Thomas Bertram, Cologne
Title: Molecular gas in nearby low-luminosity QSO host galaxies & Cophasing the Large Binocular Telescope
Date: Tue 26-Jun-2007
Speaker: Dr. Christian Holler (Oxford University)
Title: GUBBINS: the Gigahertz Ultra-broadband Interferometer for Sunyaev-Zel'dovich Effect
Interferometers are increasingly popular for observations of the cosmic microwave background. Dr. Holler will describe an experiment for spectroscopic imaging of the S-Z effect in clusters of galaxies, both from the scientific and technical perspectives.
