This week on HST

HST Programs: May 31, 2010 - June 6, 2010

Program Number Principal Investigator Program Title
11142 Lin Yan, California Institute of Technology Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3
11338 Michael R. Garcia, Smithsonian Institution Astrophysical Observatory Continued M31 Monitoring for Black Hole X-ray Nova
11519 James C. Green, University of Colorado at Boulder COS-GTO: Great Wall Tomography
11536 James C. Green, University of Colorado at Boulder COS-GTO: Sleuthing the Source of Distant Cometary Activity
11556 Marc W. Buie, Southwest Research Institute Investigations of the Pluto System
11557 Gabriela Canalizo, University of California - Riverside The Nature of low-ionization BAL QSOs
11570 Adam Riess, The Johns Hopkins University Narrowing in on the Hubble Constant and Dark Energy
11573 Lawrence Sromovsky, University of Wisconsin - Madison Investigating Post-Equinox Atmospheric Changes on Uranus
11595 John M. O'Meara, Saint Michaels College Turning out the Light: A WFC3 Program to Image z>2 Damped Lyman Alpha Systems
11605 Travis Stuart Barman, Lowell Observatory Obtaining the Missing Links in the Test of Very Low Mass Evolutionary Models with HST
11613 Roelof S. de Jong, Astrophysikalisches Institut Potsdam GHOSTS: Stellar Outskirts of Massive Spiral Galaxies
11631 Iain Neill Reid, Space Telescope Science Institute Binary brown dwarfs and the L/T transition
11643 Ann Zabludoff, University of Arizona A Timeline for Early-Type Galaxy Formation: Mapping the Evolution of Star Formation, Globular Clusters, Dust, and Black Holes
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
11648 Emanuele Daddi, Commissariat a l'Energie Atomique (CEA) WFC3 spectroscopy of an X-ray luminous galaxy cluster at z>2
11662 Misty C. Bentz, University of California - Irvine Improving the Radius-Luminosity Relationship for Broad-Lined AGNs with a New Reverberation Sample
11670 Peter Garnavich, University of Notre Dame The Host Environments of Type Ia Supernovae in the SDSS Survey
11686 Nahum Arav, Virginia Polytechnic Institute and State University The Cosmological Impact of AGN Outflows: Measuring Absolute Abundances and Kinetic Luminosities
11692 J. Christopher Howk, University of Notre Dame The LMC as a QSO Absorption Line System
11696 Matthew A. Malkan, University of California - Los Angeles Infrared Survey of Star Formation Across Cosmic Time
11704 Brian Chaboyer, Dartmouth College The Ages of Globular Clusters and the Population II Distance Scale
11712 John P. Blakeslee, Dominion Astrophysical Observatory Calibration of Surface Brightness Fluctuations for WFC3/IR
11718 Julianne Dalcanton, University of Washington The Stellar Halos of Dwarf Galaxies
11721 Richard S. Ellis, California Institute of Technology Verifying the Utility of Type Ia Supernovae as Cosmological Probes: Evolution and Dispersion in the Ultraviolet Spectra
11728 Timothy M. Heckman, The Johns Hopkins University The Impact of Starbursts on the Gaseous Halos of Galaxies
11735 Filippo Mannucci, Osservatorio Astrofisico di Arcetri The LSD project: dynamics, merging and stellar populations of a sample of well-studied LBGs at z~3
11742 Gabor Worseck, University of California - Santa Cruz Probing HeII Reionization with GALEX-selected Quasar Sightlines and HST/COS
11788 George Fritz Benedict, University of Texas at Austin The Architecture of Exoplanetary Systems
11789 George Fritz Benedict, University of Texas at Austin An Astrometric Calibration of Population II Distance Indicators
11841 John S. Mulchaey, Carnegie Institution of Washington The Formation of Brightest Cluster Galaxies
12016 Carol A. Grady, Eureka Scientific Inc. The Stars and Edge-on Disks of PDS 144: An Intermediate-Mass Analog of Wide T Tauri Multiple Stars
12018 Andrea H. Prestwich, Smithsonian Institution Astrophysical Observatory Ultra-Luminous x-Ray Sources in the Most Metal-Poor Galaxies
12117 Andrew Drake, California Institute of Technology Determining the Nature of an Exceptional Optical Transient

Selected highlights

GO 11613: GHOSTS: Stellar Outskirts of Massive Spiral Galaxies

The (relatively) nearby barred spiral galaxy, NGC 253 The subdwarf stars that populate the Galactic halo are generally recognised as fossil remnants of the first episode of substantial star formation to afflict the Milky Way galaxy. The structure and density distribution of our own halo has been inferred partly from deep starcounts, partly from globular cluster systems and partly from the kinematics of local subdwarfs; most analyses favour a near-spherical system with density r-3.5. The aim of this proposal is to extend these studies to a number of other nearby spiral systems. ACS and WFC3/UVIS are being used to obtain SNAP observations in the F606W and F814W filters in regions within the galactic halos. The observations are capable of obtaining photometry extending 2-3 magnitudes below the tip of the red giant branch in those galaxies. The data should permit separation of the contributions from disk, thick disk and bulge, and isolation of the halo population. The observations will allow measurement of the halo metallicity distribution and an estimate of the shape of the halo in these systems.

GO 11644: A dynamical-compositional survey of the Kuiper belt: a new window into the formation of the outer solar system

The architecture of the outer Solar System The Kuiper Belt lies beyond the orbit of Neptune, extending from ~30 AU to ~50 AU from the Sun, and includes at least 70,000 objects with diameters exceeding 100 km. Setting aside Pluto, the first trans-Neptunian objects were discovered in the early 1990s. Most are relatively modest in size, with diameters of a few hundred km and photometric properties that suggested an icy composition, similar to Pluto and its main satellite, Charon. Over the last three years, a handful of substantially larger bodies have been discovered, with diameters of more than 1000 km; one of the objects, 2003 UB313, is comparable in size to Pluto (2320 km.). At the same time, ground-based surveys, such as the Deep Ecliptic Survey, the Canada-France Ecliptic plane Survey and the Palomar Quest Survey, scanned the ecliptic for fainter, lower-mass objects, with the aim of using their properties to assess the likely chemical composition and dynamical history of the early Solar System. The present program will use Wide Field Camera 3 to push up to 2 magnitudes fainter than these ground-based studies, providing reliable estimates of compositions for a representative sample of KBOs.

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 11712: Calibration of Surface Brightness Fluctuations for WFC3/IR

Simulations of a nearby dwarf galaxy, a nearby giant galaxy and a distant giant galaxy; note that the last is similar in angular size to the dwarf, but has a much smoother brightness distribution (simulations from Ned Wright's ABC of distances The determination of the Cosmic Distance Scale remains one of the major goals of cosmological programs in the early 21st century. Achieving this goal requires a reliable distance indicator. While observing programs continue to pursue conventional primary distance indicators (such as RR Lyraes and Cepheids) and secondary distance indicators (such as the RGB tip and the Tully-Fisher relation), attention is also being given to the method of surface brightness fluctuations. This method rests primarily on the hypothesis that the stellar populations in most galaxies have similar colour-magnitude diagrams. Thus, the total luminosity of the galaxy is generated by similar stars - mainly red giants. In a nearby low-luminosity galaxy, most of the light comes from a relatively small numebr of giant branch stars; consequently, that galaxy has a "grainier" appearance than a distant high-luminosity galaxy of the same apparent magnitude (see figure). The degree of granularity can therefore serve as a distance indicator. The present program will use the IR channel of Wide-Field Camera 3 (F110W and F160W filters) to observe seventeen galaxies in the Fornax and Virgo clusters to provide a reliable calibration of this technique.

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