This week on HST


HST Programs: August 30, 2010 - September 5, 2010

Program Number Principal Investigator Program Title
11219 Alessandro Capetti, Osservatorio Astronomico di Torino Active Galactic Nuclei in nearby galaxies: a new view of the origin of the radio-loud radio-quiet dichotomy?
11540 James C. Green, University of Colorado at Boulder COS-GTO: Search for Hydrocarbons and Nitriles in Pluto's Atmosphere
11563 Garth D. Illingworth, University of California - Santa Cruz Galaxies at z~7-10 in the Reionization Epoch: Luminosity Functions to <0.2L* from Deep IR Imaging of the HUDF and HUDF05 Fields
11565 Sebastien Lepine, American Museum of Natural History A search for astrometric companions to very low-mass, Population II stars
11567 Charles R. Proffitt, Computer Sciences Corporation Boron Abundances in Rapidly Rotating Early-B Stars.
11588 Raphael Gavazzi, CNRS, Institut d'Astrophysique de Paris Galaxy-Scale Strong Lenses from the CFHTLS survey
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
11594 John M. O'Meara, Saint Michaels College A WFC3 Grism Survey for Lyman limit absorption at z=2
11599 Richard A. Wade, The Pennsylvania State University Distances of Planetary Nebulae from SNAPshots of Resolved Companions
11604 David J. Axon, Rochester Institute of Technology The Nuclear Structure of OH Megamaser Galaxies
11626 Philip Massey, Lowell Observatory Searching for the Upper Mass Limit in NGC 3603, the Nearest Giant H II Region
11639 Paula Szkody, University of Washington Catching Accreting WDs Moving into Their Instability Strip{s}
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
11647 Arlin Crotts, Columbia University in the City of New York A Deep Exploration of Classes of Long Period Variable Stars in M31
11657 Letizia Stanghellini, National Optical Astronomy Observatory, AURA The population of compact planetary nebulae in the Galactic Disk
11658 David A. Turnshek, University of Pittsburgh Probing the Outer Regions of M31 with QSO Absorption Lines
11663 Mark Brodwin, Smithsonian Institution Astrophysical Observatory Formation and Evolution of Massive Galaxies in the Richest Environments at 1.5 < z < 2.0
11665 Thomas M. Brown, Space Telescope Science Institute The Formation Mechanisms of Extreme Horizontal Branch Stars
11668 Anna Frebel, Smithsonian Institution Astrophysical Observatory Cosmo-chronometry and Elemental Abundance Distribution of the Ancient Star HE1523-0901
11678 Jane R. Rigby, Carnegie Institution of Washington Resolved H alpha star formation in two lensed galaxies at z=0.9
11684 Roeland P. van der Marel, Space Telescope Science Institute The First Proper Motion Measurement for M31: Dynamics and Mass of the Local Group
11714 Howard E. Bond, Space Telescope Science Institute Snapshot Survey for Planetary Nebulae in Local Group Globular Clusters
11729 Jon A. Holtzman, New Mexico State University Photometric Metallicity Calibration with WFC3 Specialty Filters
11740 Frederic J. Pont, University of Bern A Complete Optical and NIR Atmospheric Transmission Spectrum of the Exoplanet HD189733b
11840 Andrew J. Levan, The University of Warwick Identifying the host galaxies for optically dark gamma-ray bursts
12008 Albert Kong, National Tsing Hua University Primordial formation of close binaries in globular clusters with low density cores
12018 Andrea H. Prestwich, Smithsonian Institution Astrophysical Observatory Ultra-Luminous x-Ray Sources in the Most Metal-Poor Galaxies
12019 Christy A. Tremonti, University of Wisconsin - Madison After the Fall: Fading AGN in Post-starburst Galaxies
12034 James C. Green, University of Colorado at Boulder COS-GTO: Brown Dwarf Activity Part 2
12216 Steve B. Howell, National Optical Astronomy Observatory, AURA Taming the Invisible Monster with COS: Eclipse Spectroscopy of Epsilon Aurigae
12217 Philip Lucas, University of Hertfordshire Spectroscopy of faint T dwarf calibrators: understanding the substellar mass function and the coolest brown dwarfs
12232 David P. Bennett, University of Notre Dame Detection and Mass Measurement of an Isolated Brown Dwarf
12234 Wesley Fraser, California Institute of Technology Differentiation in the Kuiper belt: a search for silicates on icy bodies.
12237 William M. Grundy, Lowell Observatory Orbits, Masses, Densities, and Colors of Two Transneptunian Binaries
12296 Howard E. Bond, Space Telescope Science Institute HST Observations of Astrophysically Important Visual Binaries
12321 Christopher Johns-Krull, Rice University The Parallax of the Planet Host Star XO-3

Selected highlights

GO 11563: Galaxies at z~7-10 in the Reionization Epoch: Luminosity Functions to <0.2L* from Deep IR Imaging of the HUDF and HUDF05 Fields

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. The present program aims to extend observations beyond z~8 to z+9 or even 10 by using the WFC3-IR camera to obtain deep F850LP (Y), F105W (J) and F160W (H) images centred on the UDF and two flanking fields. Parallel observations with ACS will be used to extend the visible and red imaging data to even fainter magitudes.

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 11626: Searching for the Upper Mass Limit in NGC 3603, the Nearest Giant H II Region

Hubble WFC3 image of the star cluster, NGC 3603 NGC 3603 is a massive star-forming region located in Carina spiral arm at a distance of around 6-7 kpc from the Sun. The system is extremely young, with age estimates centering around 1 Myr for the massive stars, alkthough there are some suggestions of an underlying population of stars with ages that are higher by a factor of 3 to 4. The cluster harbours at least three Wolf-Rayet stars, as well as numerous blue supergiants. As such, the cluster is a prime candidate for tackling a long-standing question: how big a star can a star-forming region form? Theory suggests that there are a number of processes that could act to set an upper mass limit to star formation: rotational instability; disruption by photoemission processes; or gravitational instability. However, as yet there are no quantitative predictions. The current program aims to tackle this issue by using spectroscopy to probe the highest mass stars in the cluster. HST is crucial to obtaining reliable observations in such a crowded environment, and STIS will be used to survey stars inaccessible from the ground.

GO 11740: A Complete Optical and NIR Atmospheric Transmission Spectrum of the Exoplanet HD189733

Key events in a planetary transit HD 198733 is a 7th magnitude G5 dwarf that lies at a distance of ~20 parsecs from the Sun in the constellation of Vulpecula. Like many other nearby solar-type stars, HD 189733 has an associated planetary system, including a hot Jupiter, a ~1.15 MJ gas giant with an orbital period of 2.12 days. Most significantly, that inner planet transits the central star, making HD 189733 the closest transiting system found so far. Transiting systems offer a potential gold-mine for extrasolar planetary studies, since not only is the orbital inclination well defined, but the diameter (and hence the average density) is directly measureable form the eclipse depth, while the atmospheric composition can be probed through line absorption or re-radiated thermal flux. The results from these measurments can be used to test, and improve, theoretical models of extrasolar planets. These observations are best done from space: indeed, the only successful atmospheric observations to date have been with HST and Spitzer. HD 189733 has been one of the kost popular targets, with previous observations used to measure the diameter (GO 10923: ACS/HRC in Cycle 15), search for atmospheric water (GO 11117: NICMOS, Cycle 16) and sodium (GO 11572: STIS, Cycle 17), and probe the outer atmospheric dynamics (GO 11572: STIS, Cycle 17). The present program uses STIS and the WFC3/IR grisms to map the optical/near-IR spectral energy distribution through transit.

Past weeks:
page by Neill Reid, updated 12/8/2010