This week on HST


HST Programs: January 17, 2011 - January 23, 2011

Program Number Principal Investigator Program Title
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
11597 S. Adam Stanford, University of California - Davis Spectroscopy of IR-Selected Galaxy Clusters at 1 < z < 1.5
11696 Matthew A. Malkan, University of California - Los Angeles Infrared Survey of Star Formation Across Cosmic Time
11705 Frederick W. Hamann, University of Florida Physical Properties of Quasar Outflows: From BALs to mini-BALs
11728 Timothy M. Heckman, The Johns Hopkins University The Impact of Starbursts on the Gaseous Halos of Galaxies
11840 Andrew J. Levan, The University of Warwick Identifying the host galaxies for optically dark gamma-ray bursts
12009 Anja von der Linden, Stanford University Anatomy of a merger: the curious case of MACS J0417.5-1154
12056 Julianne Dalcanton, University of Washington A Panchromatic Hubble Andromeda Treasury - I
12061 Sandra M. Faber, University of California - Santa Cruz Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey -- GOODS-South Field, Early Visits of SNe Search
12065 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12099 Adam Riess, The Johns Hopkins University Supernova Follow-up for MCT
12166 Harald Ebeling, University of Hawaii A Snapshot Survey of The Most Massive Clusters of Galaxies
12169 Boris T. Gaensicke, The University of Warwick The frequency and chemical composition of planetary debris discs around young white dwarfs
12178 Scott F. Anderson, University of Washington Spanning the Reionization History of IGM Helium: a Highly Efficient Spectral Survey of the Far-UV-Brightest Quasars
12184 Xiaohui Fan, University of Arizona A SNAP Survey for Gravitational Lenses Among z~6 Quasars
12196 David J. Radburn-Smith, University of Washington Disk Truncations: Probing Galaxy Formation at the Limits
12197 Johan Richard, University of Durham Evolution in the Size-Luminosity Relation of HII regions in Gravitationally-lensed galaxies
12203 S. Adam Stanford, University of California - Davis Rest Frame Optical Spectroscopy of Galaxy Clusters at 1.6 < z < 1.9
12210 Adam S. Bolton, University of Utah SLACS for the Masses: Extending Strong Lensing to Lower Masses and Smaller Radii
12212 D. Michael Crenshaw, Georgia State University Research Foundation What are the Locations and Kinematics of Mass Outflows in AGN?
12224 Naveen A. Reddy, National Optical Astronomy Observatory, AURA Measuring the Stellar Populations of Individual Lyman Alpha Emitters During the Epoch of Peak Star Formation
12229 Linda J. Smith, Space Telescope Science Institute HST U-band Survey of Star Clusters in Nearby Star-Forming Galaxies
12236 Lisa Glass, Dominion Astrophysical Observatory The Nuclear to Global Connection: a Detailed View of Compact Stellar Nuclei in a Complete Sample of Virgo Ellipticals
12242 Robert P. Kirshner, Harvard University UV Studies of a Core Collapse Supernova
12283 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey {WISP}: A Survey of Star Formation Across Cosmic Time
12290 Michael Jura, University of California - Los Angeles Do Rocky Extrasolar Minor Planets Have a Composition Similar to Bulk Earth?
12292 Tommaso L. Treu, University of California - Santa Barbara SWELLS: doubling the number of disk-dominated edge-on spiral lens galaxies
12307 Andrew J. Levan, The University of Warwick A public SNAPSHOT survey of gamma-ray burst host galaxies
12308 Eric M. Monier, State University of New York College at Brockport Cosmic Metallicity from ZnII-Selected QSO Absorption Line Systems Near Redshift z=1.2
12310 Goeran Oestlin, Stockholm University LARS - The Lyman Alpha Reference Sample
12319 Slawomir Stanislaw Piatek, New Jersey Institute of Technology Proper Motion Survey of Classical and SDSS Local Group Dwarf Galaxies
12324 C. S. Kochanek, The Ohio State University The Temperature Profiles of Quasar Accretion Disks
12433 Kandis Lea Jessup, Southwest Research Institute Coordinated HST, Venus Express, and Venus Climate Orbiter Observations of Venus

Selected highlights

GO 11728: The Impact of Starbursts on the Gaseous Halos of Galaxies

A computer simulation of galactic gas accretion and outflow The detailed history of galaxy formation and assembly depends on the availability of gas for star formation, and on how processes engendered by that star formation affects the distribution and intrinsic properties of that gas. In particular, feedback in the form of winds and ionising radiation from either young stellar associations or massive black holes may be capable of interfering with, and even interrupting, the overall assembly process. The present program aims to investigate this issue by probing the nature of halo gas in the vicinity of galaxies that have undergone recent (<100 Myr old) starbursts. The halo gas is expected to reside predominantly at high temperatures. The most effective means of detecting such gas is through ultraviolet spectroscopy, where gas within nearby systems can be detected as absorption lines superimposed on the spectra of more distant objects, usually quasars. The present program is using the Cosmic Origins Spectrograph to observe moderate-redshift QSOs that lie at small angular separations from the starburst galaxies. The sightlines run through the halos of the galaxies, and the QSOs therefore provide a pencilbeam backlight that probes hot gas in the foreground systems.

GO 12056: A Panchromatic Hubble Andromeda Treasury

M31: the Andromeda spiral galaxy M31, the Andromeda galaxy, is the nearest large spiral system to the Milky Way (d ~ 700 kpc), and, with the Milky Way, dominates the Local Group. The two galaxies are relatively similar, with M31 likely the larger system; thus, Andromeda provides the best opportunity for a comparative assessment of the structural properties of the Milky Way. Moreover, while M31 is (obviously) more distant, our external vantage point can provide crucial global information that complements the detailed data that we can acquire on individual members of the stellar populations of the Milky Way. With the advent on the ACS and, within the last 2 years, WFC3 on HST, it has become possible to resolve main sequence late-F and G dwarfs, permitting observations that extend to sub-solar masses in M31's halo and disk. Initially, most attention focused on the extended halo of M31 (eg the Cycle 15 program GO 10816 ), with deep imaging within a limited number of fields revealing the complex metallicity structure within that population. With the initiation of the present Multi-Cycle Treasury program, attention switches to the M31 disk. "PHAT" will conduct a multi-waveband survey of approximately one third of disk and bulge, focusing on the north-east quadrant. Observations will extend over the next three cycles, and will provide a thorough census of upper main-sequence stars and star forming regions, matching the stellar distribution against the dust and gas distribution.
GO 12184: A SNAP Survey for Gravitational Lenses Among z~6 Quasars

Temporal variation in the intensities of the lensed components of the Einstein Cross Gravitational lensing is a consequence 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 primarily to probe the mass distribution of galaxy clusters, using theoretical models to analyse the arcs and arclets that are produced by strong lensing of background galaxies, and the large-scale mass distribution, through analysis of weak lensing effects on galaxy morphologies. Gravitational lensing also increases the apparent brightness of the background sources. This effect can be used to our advantage, in enabling detailed observations of high-redshift sources that be too faint to observe under normal circumstances, but it can also lead to statistical biases in parameters such as luminosity functions. These effects are likely to be of most importance for higher redshift sources, where the longer pathlength leads to a higher probability of the light encountering a foreground lens. The present program aims to address this issue for by using WFC3 to obtain high resolution images F105W ("Y"-band) of a subset of 54 QSOs with redshifts in the range 5.7 < z < 6.4.

GO 12290: Do Rocky Extrasolar Minor Planets Have a Composition Similar to Bulk Earth?

Artist's impression of a comet spiralling in to the white dwarf variable, G29-38 White dwarf stars are the final evolutionary state of stars like the Sun. Comprised of degenerate material that compacts more than half the mass of the Sun into a radius comparable with that of the earth, white dwarfs have no internal energy source, and gradually cool and fade with time. At higher temperatures (> 10,000K), their spectra are dominated by broad lines of either hydrogen (DA white dwarfs) or helium (DBs). A handful of spectroscopic oddities, with prominent metal lines (Ca, Mg) were discovered in the 1970s and 80s. Those elements are predicted to diffuse relatively rapidly within the white dwarf atmosphere, and those objects were typically explained as resulting from interstellar accretion. However, high resolution optical spectroscopy obtained in the late 1990s revealed that a significant fraction of DA white dwarfs have narrow metallic absorption lines. Crucially, one of the stars found to have such absorption features is G29-38, the white dwarf originally tagged as harbouring a brown dwarf companion based on its showing a strong mid-infrared excess. Given the relatively high frequency of occurrence and the short residence time in the atmosphere, interstellar accretion is not an option, and those lines must be maintained by continuous accretion from a circumstellar debris disk (which contributes the IR excess in G 29-38). That debris disk, in turn, must be regularly replenished, presumably from collisions between rocky remnants of a solar system. Thus, probing the abundance distribution of the accreted material should illuminate the composition of the residual asteroidal material. The present program aims to tackle this issue by using the Cosmic Origins Spectrograph to obtain UV spectra of a sample of 6 white dwarfs known to exhibit metallic absorption lines.

Past weeks:
page by Neill Reid, updated 1/15/2011