This week on HST

HST Programs: March 15, 2010 - March 21, 2010

Program Number Principal Investigator Program Title Links
11149 Eiichi Egami, University of Arizona Characterizing the Stellar Populations in Lyman-Alpha Emitters and Lyman Break Galaxies at 5.7 Abstract
11166 Jong-Hak Woo, University of California - Santa Barbara The Mass-dependent Evolution of the Black Hole-Bulge Relations Abstract
11202 Leon Koopmans, Kapteyn Astronomical Institute The Structure of Early-type Galaxies: 0.1-100 Effective Radii Abstract
11235 Jason A. Surace, California Institute of Technology HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies in the Local Universe Abstract
11360 Robert W. O'Connell, The University of Virginia Star Formation in Nearby Galaxies Abstract
11548 S. Thomas Megeath, University of Toledo NICMOS Imaging of Protostars in the Orion A Cloud: The Role of Environment in Star Formation Abstract
11550 James Green, University of Colorado at Boulder COS-GTO: X-Ray Binaries Abstract
11567 Charles R. Proffitt, Computer Sciences Corporation Boron Abundances in Rapidly Rotating Early-B Stars. Abstract
11570 Adam Riess, The Johns Hopkins University & Space Telescope Science Institute Narrowing in on the Hubble Constant and Dark Energy Abstract
11577 Brad C. Whitmore, Space Telescope Science Institute Opening New Windows on the Antennae with WFC3 Abstract
11592 Nicolas Lehner, University of Notre Dame Testing the Origin(s) of the Highly Ionized High-Velocity Clouds: A Survey of Galactic Halo Stars at z>3 kpc Abstract
11594 John M. O'Meara, Saint Michaels College A WFC3 Grism Survey for Lyman limit absorption at z=2 Abstract
11595 John M. O'Meara, Saint Michaels College Turning out the Light: A WFC3 Program to Image z>2 Damped Lyman Alpha Systems Abstract
11603 Jennifer Andrews, Louisiana State University and A & M College A Comprehensive Study of Dust Formation in Type II Supernovae with HST, Spitzer and Gemini Abstract
11611 D. Michael Crenshaw, Georgia State University Research Foundation Are Narrow-Line Seyfert 1 Galaxies Viewed Pole-on? Abstract
11613 Roelof S. de Jong, Astrophys. Inst. Potsdam GHOSTS: Stellar Outskirts of Massive Spiral Galaxies Abstract
11639 Paula Szkody, University of Washington Catching Accreting WDs Moving into Their Instability Strip(s Abstract
11644 Michael E. Brown, California Institute of Technology A dynamical-compositional survey of the Kuiper belt: a new window into the formation of the outer solar system Abstract
11657 Letizia Stanghellini, National Optical Astronomy Observatories The population of compact planetary nebulae in the Galactic Disk Abstract
11677 Harvey B. Richer, University of British Columbia Is 47 Tuc Young? Measuring its White Dwarf Cooling Age and Completing a Hubble Legacy Abstract
11687 Thomas R. Ayres, University of Colorado at Boulder SNAPing Coronal Iron Abstract
11696 Matthew A. Malkan, University of California - Los Angeles Infrared Survey of Star Formation Across Cosmic Time Abstract
11700 Michele Trenti, University of Colorado at Boulder Bright Galaxies at z>7.5 with a WFC3 Pure Parallel Survey Abstract
11701 Tommaso L. Treu, University of California - Santa Barbara The jackpot in technicolor: photometric redshift and mass to light decomposition of a double Einstein Ring Abstract
11702 Hao-Jing Yan, Carnegie Institution of Washington Search for Very High-z Galaxies with WFC3 Pure Parallel Abstract
11704 Brian Chaboyer, Dartmouth College The Ages of Globular Clusters and the Population II Distance Scale Abstract
11705 Frederick W. Hamann, University of Florida Physical Properties of Quasar Outflows: From BALs to mini-BALs Abstract
11728 Timothy M. Heckman, The Johns Hopkins University The Impact of Starbursts on the Gaseous Halos of Galaxies Abstract
11730 Nitya Jacob Kallivayalil, Massachusetts Institute of Technology Continued Proper Motions of the Magellanic Clouds: Orbits, Internal Kinematics, and Distance Abstract
11732 C. S. Kochanek, The Ohio State University Research Foundation The Temperature Profiles of Quasar Accretion Disks Abstract
11741 Todd Tripp, University of Massachusetts Probing Warm-Hot Intergalactic Gas at 0.5 < z < 1.3 with a Blind Survey for O VI, Ne VIII, Mg X, and Si XII Absorption Systems Abstract

Selected highlights

GO 11696: Infrared Survey of Star Formation Across Cosmic Time

A region of massive star formation Star formation is the key astrophysical process in determining the overall evolution of galactic systems, the generation of heavy elements, and the overall enrichment of interstellar and intergalactic material. Tracing the overall evolution through a wide redshift range is crucial to understanding how gas and stars evolved to form the galaxies that we see around us now. The present program builds on the ability of HST to carry out parallel observations, using more than one instrument. While the Cosmic Origins Spectrograph is focused on obtaining ultraviolet spectra of unparalleled signal-to-noise, this program uses the near-infrared grisms mounted on the Wide-Field Camera 3 infrared channel to obtain low resolution spectra between 1 and 1.6 microns of randomly-selected nearby fields. The goal is to search for emission lines characteristic of star-forming regions. In particular, these observations are capable of detecting Lyman-alpha emission generated by star formation at redshfits z > 5.6. A total of up to 40 "deep" (4-5 orbit) and 20 "shallow" (2-3 orbit) fields will be targeted in the course of this observing campaign.

GO 11730: Continued Proper Motions of the Magellanic Clouds: Orbits, Internal Kinematics, and Distance

The Large Magellanic Cloud (upper left) with the Small Magellanic Cloud (right) and the (foreground) Galactic globular cluster47 Tucanae The Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC) are the most massive satellites of the Milky Way galaxy. The orbital motions of these systems can be used to probe the mass distribution of Milky Way, and backtracking the orbits can shed light on how the three systems have interacted, In particular, the well known Magellanic Stream, stretching between the two Clouds, is thought to be a product either of interactions between the Clouds, or of ram-stripping of gas from the LMC on its last passage through the Plane of the Milky Way. The present program builds on observations obtained at three previous epochs with the now-defunct ACS High Resolution Camera (ACS/HRC) and, in Cycle 16, with the Planetary camera on WFPC2. The previous programs targeted known QSOs lying behind the Clouds; the QSOs serve as fixed reference points for absolute astrometry of the numerous foreground LMC/SMC stars. First epoch observations were made in late 2002 (GO 9462), with the follow-up imaging in late 2004 (GO 10130) and 2007/2008 (GO 11201). The tangential motions of the Clouds amount to only a few milliarcseconds, but the high spatial resolution and high stability of HST imaging makes such measurements possible, even with only a 2-year baseline. Surprisingly, the initial results suggest that the 3-D motions of both clouds are much higher than expected, suggesting either that the LMC/SMC/MW is either dynamically very young, or unbound. The present program will use WFC3 to obtain fourth-epoch data in the same fields, providing a further crucial test of the initial results

GO 11732: The Temperature Profiles of Quasar Accretion Disks

The first Einstein cross, the gravitational lensed QSO, G2237+0305 Gravitational lensing is a consequence the theory of general relativity. Its importance as an astrophysical tool first became apparent with the realisation (in 1979) that the quasar pair Q0957+561 actually comprised two lensed images of the same background quasar. In the succeeding years, lensing has been used to probe the mass distributions on a variety of scales: of galaxies (primarily via multiply-imaged quasars); of galaxy clusters (arcs and arclets); and at the largest scales (weak lensing). However, lensing can also provide insight on the small-scale properties of the object being lensed. In a lensed QSO, the light from the QSO follows different paths to produce the separate images; each of those paths has a different length; consequently, flux variations in the source show up at different times in the separate images. The present program aims to take advantage of this property to probe the structure of the accretion disks surrounding the central black hole in a number of lensed QSOs. The program will combine ultraviolet observations with the WFC3/UVIS camera on HST with GALEX UV data for 5 lenses spanning as broad range of black hole masses. Studying the variation as a function of wavelength should probe the accretion disk structure, since light from the inner regions are expected to dominate at shorter wavelengths, while the outer regions dominate at longer wavelengths.

GO 11741: Probing Warm-Hot Intergalactic Gas at 0.5 < z < 1.3 with a Blind Survey for O VI, Ne VIII, Mg X, and Si XII Absorption Systems

Probing the intergalactic medium via QSO absorption lines One of the key issues facing modern cosmology is the "missing baryon" problem. In brief, a census of all the constituents in the local universe accounts for less than half of the baryonic mass expected based on measurements of the fractional abundanmce of deuterium and observations of the cosmic microwave background. It is generally believed that the missing material lurks in the form of extremely hot gas in the intergalactic medium. The most effective means of probing that medium, and testing this hypothesis, is to search for the appropriate absorption lines in the spectrum of a background source. QSOs are particularly effective cosmic searchlights, since they have strong continuum flux levels at the ultraviolet wavelengths where most of the important absorption lines fall. Following SM4, and the installation of the Cosmic Origins Spectrograph, HST is now well equipped to tackle this type of program, and search fgor a full accounting of the baryonic universe. The present program weill use COS to obtain spectra of nine QSOs at redshifts beyond z=0.89, and will search for warm-hot intergalactic gas in the redshift range 0.5 < z < 1.3.

Past weeks:
page by Neill Reid, updated 19/2/2010