This week on HST

HST Programs: August 29, 2011 - September 4, 2011

Program Number Principal Investigator Program Title
11670 Peter Garnavich, University of Notre Dame The Host Environments of Type Ia Supernovae in the SDSS Survey
12023 James C. Green, University of Colorado at Boulder COS-GTO: Cold ISM
12031 James C. Green, University of Colorado at Boulder COS-GTO: Sampling the Local ISM with hot white dwarfs - Part 2
12035 James C. Green, University of Colorado at Boulder COS-GTO: Activity of Solar Mass Stars from Cradle to Grave Part 2
12039 James C. Green, University of Colorado at Boulder COS-GTO: X-Ray Binaries
12099 Adam Riess, The Johns Hopkins University Supernova Follow-up for MCT
12102 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12103 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12106 Julianne Dalcanton, University of Washington A Panchromatic Hubble Andromeda Treasury - I
12169 Boris T. Gaensicke, The University of Warwick The frequency and chemical composition of planetary debris discs around young white dwarfs
12177 Pieter van Dokkum, Yale University 3D-HST: A Spectroscopic Galaxy Evolution Treasury
12185 Jenny E. Greene, University of Texas at Austin The Hosts of Megamaser Disk Galaxies
12188 Jay B. Holberg, University of Arizona Tests of Extreme Physics in Very Cool White Dwarfs
12190 Anton M. Koekemoer, Space Telescope Science Institute WFC3/IR Spectroscopy of the Highest Redshift Black Hole Candidates
12192 James T. Lauroesch, University of Louisville Research Foundation, Inc. A SNAPSHOT Survey of Interstellar Absorption Lines
12206 Mark S. Westmoquette, European Southern Observatory - Germany Starburst-driven shocks and feedback in the near-IR at high resolution
12239 Gilda E. Ballester, University of Arizona Springtime at Uranus: Upheaval in the Stratosphere?
12254 Adrienne Cool, San Francisco State University Helium-core White Dwarfs and Cataclysmic Variables in NGC 6752: New Clues to the Dynamical Evolution of Globular Clusters
12269 Claudia Scarlata, University of Minnesota - Twin Cities The escape of Lya photons in star-forming galaxies
12272 Christy A. Tremonti, University of Wisconsin - Madison Testing Feedback: Morphologies of Extreme Post-starburst Galaxies
12283 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey {WISP}: A Survey of Star Formation Across Cosmic Time
12298 Richard S. Ellis, California Institute of Technology Towards a Physical Understanding of the Diversity of Type Ia Supernovae
12307 Andrew J. Levan, The University of Warwick A public SNAPSHOT survey of gamma-ray burst host galaxies
12320 Brian Chaboyer, Dartmouth College The Ages of Globular Clusters and the Population II Distance Scale
12330 J. Davy Kirkpatrick, California Institute of Technology Spitzer Verification of the Coldest WISE?selected Brown Dwarfs
12514 Karl Stapelfeldt, NASA Goddard Space Flight Center Imaging of Newly-identified Edge-on Protoplanetary Disks in Nearby Star-Forming Regions
12549 Thomas M. Brown, Space Telescope Science Institute The Formation History of the Ultra-Faint Dwarf Galaxies
12576 Paul Kalas, University of California - Berkeley Orbit determination for Fomalhaut b and the origin of the debris belt halo
12686 Stephen Bradley Cenko, University of California - Berkeley Sw J2058+05: A Possible Second Relativistic Tidal Disruption Flare

Selected highlights

GO 12016: 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 12239:Spingtime for Uranus: Upheaval in the stratosphere?

Hubble ACS image of Uranus from 2004
Uranus is unique among the major bodies in the Solar System in that it rotates on its side. Unlike the other planets, the polar obliquity is 98o degrees, so the equator is alomost perpendicular to the ecliptic plane. Consequently, as Uranus circles the Sun, each pole spends almost half of a Uranian "year" (or 42 terrestrial years) hidden from the Sun in total darkness. Perhaps as a result, the Uranian upper atmosphere is significantly different than the atmospheres of the other solar system gas giants. Observations by Voyager 2 during its 1986 flyby showed that Uranus has a hot thermosphere and extensive corona, but a very quiescent stratosphere. At that time, the polar axis was almost directly pointed towards the Sun. On December 7th 2007, Uranus passed through its equinox, and the Sun now passes directly overhead at the Uranian equator. The present program will use STIS to obtain far-UV spectra of Uranian airglow within the upper atmosphere. Those observations will be compared with similar data from Voyar=ger 2 to determine the extent of seasonal variations in the structure of the upper atmosphere.

GO 12254: Helium-core White Dwarfs and Cataclysmic Variables in NGC 6752: New Clues to the Dynamical Evolution of Globular Clusters

The intermediate-metallicity cluster, NGC 6752
Lying at a distance of ~4 kpc in the southern constellation of Pavo, NGC 6752 is the third brightest globular cluster and one of the closest to the Sun. It is moderately metal-poor, with a metallicity [Fe/H] ~ -1.5, or ~3% that of the Sun. Given its proximity and the relatively low reddening due to foreground dust, NGC 6752 has received substantial observational attention since its discovery in the mid 1820s by the Scots astronomer, James Dunlop. [At the time, Dunlop was working for Sir Thomas Brisbane at Paramatta Observatory, NSW.] Ground-based and HST observations reveal a colour-magnitude diagram characterised by an extended horizontal branch, a main sequence of some modest width, diverse abundances on the giant branch and a number of white dwarfs outlining a degenerate sequence. Recent detailed observations suggest that this cluster harbours multiple stellar populations. The present program focuses on the white dwarfs, using a combination of blue and red, wide- and narrow-band imaging with the Wide-Field camera on ACS in an attempt to identify candidate binary systems, both double-degenerates and cataclysmic variables.

GO 12298: Towards a Physical Understanding of the Diversity of Type Ia Supernovae

The discovery image of the August 2011 SNe in M101
Supernovae are the most spectacular form of stellar obituary. Since B2FH, the physical processes underlying their eruptive deaths have been known to play a key role in populating the ISM with metals beyond the iron peak. More recently, these celestial explosions have acquired even greater significance through the use of Type Ia supernovae as distance indicators in mapping the `dark energy' acceleration term of cosmic expansion. However, while there are well-established models for the two main types of supernovae (runaway fusion on the surface of a white dwarf in a binary system for Type Ia, or detonation of the core in Type II), some significant uncertainties remain concerning the physical details of the disruption, and, potentially, the overall uniformity of these events. Consequently, there is potential for systematic bias in the distance estimates. The present program aims to address this issue through detailed observations of a small number of relatively nearby Type Ia Sne. The program aims to pick up the supernovae well before maximum, permitting detailed UV spectroscopy on the rising side of the light curve, and following the spectral evolution to well past maximum. The SNe targets are selected from observations made by the Palomar Transit Factory, an on-going monitoring prorgam using the 60-inch telescope on Palomar mountain. The present observations target the type Ia supernova designated as PTF11kly in the nearby galaxy, M101, discovered on August 25th by the Palomar Transit Factory. This object is of particular interest, since archival HST images allow a search for the possible progenitor.

Past weeks:
page by Neill Reid, updated 2/5/2011