This week on HST

HST Programs: April 19, 2010 - April 25, 2010

Program Number Principal Investigator Program Title Links
11523 James Green, University of Colorado at Boulder COS-GTO: COS and WFC3 Observations of I Zwicky 18 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
11556 Marc W. Buie, Southwest Research Institute Investigations of the Pluto System Abstract
11565 Sebastien Lepine, American Museum of Natural History A search for astrometric companions to very low-mass, Population II stars Abstract
11568 Seth Redfield, Wesleyan University A SNAPSHOT Survey of the Local Interstellar Medium: New NUV Observations of Stars with Archived FUV Observations Abstract
11570 Adam Riess, The Johns Hopkins University & Space Telescope Science Institute Narrowing in on the Hubble Constant and Dark Energy 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
11597 S. Adam Stanford, University of California - Davis Spectroscopy of IR-Selected Galaxy Clusters at 1 < z < 1.5 Abstract
11600 Benjamin Weiner, University of Arizona Star formation, extinction and metallicity at 0.7 Abstract
11602 Sahar S. Allam, Fermi National Accelerator Laboratory High-resolution imaging of three new UV-bright lensed arcs Abstract
11606 Dan Batcheldor, Rochester Institute of Technology Dynamical Hypermassive Black Hole Masses Abstract
11625 Ivan Hubeny, University of Arizona Beyond the classical paradigm of stellar winds: Investigating clumping, rotation and the weak wind problem in SMC O stars 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
11650 William M. Grundy, Lowell Observatory Mutual Orbits, Colors, Masses, and Bulk Densities of 3 Cold Classical Transneptunian Binaries Abstract
11662 Misty C. Bentz, University of California - Irvine Improving the Radius-Luminosity Relationship for Broad-Lined AGNs with a New Reverberation Sample Abstract
11663 Mark Brodwin, Harvard University Formation and Evolution of Massive Galaxies in the Richest Environments at 1.5 < z < 2.0 Abstract
11670 Peter Garnavich, University of Notre Dame The Host Environments of Type Ia Supernovae in the SDSS Survey Abstract
11687 Thomas R. Ayres, University of Colorado at Boulder SNAPing Coronal Iron Abstract
11691 Paul Goudfrooij, Space Telescope Science Institute Using Massive Star Clusters in Merger Remnants To Provide Reference Colors of Intermediate-Age Stellar Populations Abstract
11696 Matthew A. Malkan, University of California - Los Angeles Infrared Survey of Star Formation Across Cosmic Time Abstract
11702 Hao-Jing Yan, Carnegie Institution of Washington Search for Very High-z Galaxies with WFC3 Pure Parallel Abstract
11714 Howard E. Bond, Space Telescope Science Institute Snapshot Survey for Planetary Nebulae in Local Group Globular Clusters Abstract
11715 Howard E. Bond, Space Telescope Science Institute The Luminous Galactic Cepheid RS Puppis: A Geometric Distance from its Nested Light Echoes Abstract
11717 S Bradley Cenko, California Institute of Technology Unraveling the Mysterious Origin of GRB 070125 Abstract
11727 Timothy M. Heckman, The Johns Hopkins University UV spectroscopy of Local Lyman Break Galaxy Analogs: New Clues to Galaxy Formation in the Early Universe Abstract
11728 Timothy M. Heckman, The Johns Hopkins University The Impact of Starbursts on the Gaseous Halos of Galaxies Abstract
11731 C. S. Kochanek, The Ohio State University Research Foundation Studying Cepheid Systematics in M81: H-band Observations Abstract
11732 C. S. Kochanek, The Ohio State University Research Foundation The Temperature Profiles of Quasar Accretion Disks Abstract
12051 Saul Perlmutter, University of California - Berkeley Cross Calibration of NICMOS and WFC3 in the Low-Count-Rate Regime Abstract
12077 David Jewitt, University of California - Los Angeles Monitoring the Aftermath of an Asteroid Impact Event Abstract

Selected highlights

GO 11556: Investigations of the Pluto System

Hubble Space Telescope image of Pluto, Charon and the two new moons, Nix & Hydra Pluto, one of the largest members of the Kuiper Belt and, until recently (still, for some), the outermost planet in the solar system, has been in the news over the last year or two. Besides the extended "planet"/"dwarf planet" debate, Pluto is the primary target of the New Horizons Mission, and Hubble observations in 2005 led to the discovery of two small moons. Together with Charon, itself only discovered in 1978, these additions make Pluto a 4-body system. Christened Nix and Hydra, the two new moons are 5,000 fainter than Pluto itself, implying diameters as small as ~30-50 km if the surface composition is similar to Pluto itself. The present program aims to better characterise these bodies through multicolour observations with WFC3. The observations are phased with a cadence that samples the different orbital periods: 6.4 days for Pluto/Charon; 24.9 days for Nix/Pluto; and 38 days for Hydra/Pluto. The goal is toidentify systematic photometric variations that might probe the rotation period, testing whether these moons are in synchronous rotation with Pluto itself.

GO 11565: A search for astrometric companions to very low-mass, Population II stars

HST image of Gliese 623AB, a nearby disk-dwarf binary system Binary stars provide an important avenue for setting constraints on stellar evolution, particularly binary stars that consist of components with significantly different masses. The simplest means of producing stars in a dynamically bound system is during the formation process; consequently, it is reasonable to assume that the the stars are coeval and a comparison between the observed properties and predictions can constrain stellar models. Binary systems are common in stars in the Galactic disk, although the overall frequency does decrease with stellar mass, ranging from ~60-70% for G dwarfs to closer to 20% for late-type M dwarfs and ultracool dwarfs. Binaries are much rarer among the metal-poor members of the Galactic halo, with only a handful known among cool, late-type subdwarfs. The present program aims to expand the sample by using WFC3 on HST to image low-mass, metal-poor subdwarfs within 120 parsecs of the Sun, searching for close, faint companions that can be monitored for astrometric orbit determinations.

GO 11670: The Host Environments of Type Ia Supernovae in the SDSS Survey

SN 2007uy and 2008D in NGC 2770 Supernovae have long attracted the attention of both amateur and professional astronomers as a means of studying the violent eruption and death of massive stars and degenerates. However, in the last decade they have also acquired considerable importance as distance indicators, tracing the expansion of the universe to redshifts well beyond the reach of more conventional yardsticks, such as cepheids, and providing a key underpinning for the hypothesised existcen of dark energy. Understanding the supernovae themselves, and, in particular, their progenitors, is key to accurately interpreting their luminosities and distances. The present program aims to tackle that aspect of the problem by using ACS to obtain deep, high resolution images of galaxies that have harboured recent type Ia supernovae. The targets are all drawn from the Sloan Digital Sky Survey, which has uncovered more than than 500 type Ia supernovae,. The supernovae themselves are long gone from view, but the ACS data will be used to probe the stellar populations in the immediate vicinity of the explosion, and hence gain a better understanding of the likely progenitor.

GO 11702: Search for Very High-z Galaxies with WFC3 Pure Parallel

The ACS optical/far-red image of the Hubble Ultra Deep Field Galaxy evolution in the early Universe is a discipline of astronomy that has been transformed by observations with the Hubble Space Telescope. The original Hubble Deep Field, the product of 10 days observation in December 1995 of a single pointing of Wide Field Planetary Camera 2, demonstrated conclusively that galaxy formation was a far from passive process. The images revealed numerous blue disturbed and irregular systems, characteristic of star formation in galaxy collisions and mergers. Building on this initial progam, the Hubble Deep Field South (HDFS) provided matching data for a second southern field, allowing a first assessment of likely effects due to field to field cosmic variance, and the Hubble Ultra-Deep Field (UDF) probed to even fainter magitude with the Advanced Camera for Surveys (ACS). The highest redshift objects found in the UDF have redshifts approaching z~7. Pushing to larger distances, and greater ages, demands observatons at near-infrared wavelengths, as the characteristics signatures of star formation are driven further redward in the spectrum. Wide Field Camera 3, installed in Servicing Mission 4, is well suited to these observations, and a number of programs are in place in Cycle 17 that address these issues. Indeed, WFC3 is employed in pure parallel mode by several programs. These take advantage of other science programs, usually with COS, that involve 2-5 orbit pointings on sources at high galactic latitude. The WFC3 pointing is unplanned, since it depends on the orientation adopted for the prime observations, but 2-5 orbits of IR imaging can reach galaxies at redshifts exceeding z=7 (potentially even z~8) in high latitude fields. This is one of two such programs in the cycle 17 portfolio.

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