This week on HST


HST Programs: April 25, 2011 - May 1, 2011

Program Number Principal Investigator Program Title
11528 James C. Green, University of Colorado at Boulder COS-GTO: Studies of the HeII Reionization Epoch
11557 Gabriela Canalizo, University of California - Riverside The Nature of low-ionization BAL QSOs
11598 Jason Tumlinson, Space Telescope Science Institute How Galaxies Acquire their Gas: A Map of Multiphase Accretion and Feedback in Gaseous Galaxy Halos
11696 Matthew A. Malkan, University of California - Los Angeles Infrared Survey of Star Formation Across Cosmic Time
11728 Timothy M. Heckman, The Johns Hopkins University The Impact of Starbursts on the Gaseous Halos of Galaxies
12024 James C. Green, University of Colorado at Boulder COS-GTO: Great Wall Tomography - Part 2
12025 James C. Green, University of Colorado at Boulder COS-GTO: QSO Absorbers, Galaxies and Large-scale Structures in the Local Universe Part 2
12027 James C. Green, University of Colorado at Boulder COS-GTO: STAR FORMATION/LYMAN-ALPHA Part 2
12037 James C. Green, University of Colorado at Boulder COS-GTO: NUV Spectra of Bright Kuiper Belt Objects Part 2
12066 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12069 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12163 Aaron J. Barth, University of California - Irvine Structure and Stellar Content of the Nearest Nuclear Clusters in Late-Type Spiral Galaxies
12165 Jean-Michel Desert, Harvard University Characterizing the UV environment of GJ1214b
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
12210 Adam S. Bolton, University of Utah SLACS for the Masses: Extending Strong Lensing to Lower Masses and Smaller Radii
12215 Nancy R. Evans, Smithsonian Institution Astrophysical Observatory Searching for the Missing Low-Mass Companions of Massive Stars
12241 Robert P. Kirshner, Harvard University SAINTS - The SN 1987A Intensive Study
12248 Jason Tumlinson, Space Telescope Science Institute How Dwarf Galaxies Got That Way: Mapping Multiphase Gaseous Halos and Galactic Winds Below L*
12249 Wei Zheng, The Johns Hopkins University Reionization of Intergalactic Helium at the Highest Redshifts
12262 Justyn R. Maund, University of Copenhagen, Niels Bohr Institute Stellar Forensics II: A post-explosion view of the progenitors of core-collapse supernovae
12269 Claudia Scarlata, California Institute of Technology The escape of Lya photons in star-forming galaxies
12276 Bart P. Wakker, University of Wisconsin - Madison Mapping a nearby galaxy filament
12277 Daniel E. Welty, University of Illinois at Urbana - Champaign HD 62542: Probing the Bare, Dense Core of an Interstellar Cloud
12279 Thomas R. Ayres, University of Colorado at Boulder FK Comae, King of Spin: the Movie
12283 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey {WISP}: A Survey of Star Formation Across Cosmic Time
12289 J. Christopher Howk, University of Notre Dame A COS Snapshot Survey for z < 1.25 Lyman Limit Systems
12299 Michael Eracleous, The Pennsylvania State University Spectroscopic Signatures of Binary and Recoiling Black Holes
12310 Goran Ostlin, Stockholm University LARS - The Lyman Alpha Reference Sample
12315 Hans Moritz Guenther, Smithsonian Institution Astrophysical Observatory Winds, accretion and activity: Deciphering the FUV lines in TW Hya
12326 Keith S. Noll, Space Telescope Science Institute Hubble Heritage 2.0
12376 Vinay Kashyap, Smithsonian Institution Astrophysical Observatory The Spinning Corona of FK Comae

Selected highlights

GO 11598: How Galaxies Acquire their Gas: A Map of Multiphase Accretion and Feedback in Gaseous Galaxy Halos

A computer simulation of galactic gas accretion and outflow Galaxy formation, and the overall history of star formation within a galaxy, clearly demands the presence of gas. The detailed evolution therefore depends on how gas is accreted, recycled, circulated through the halo and, perhaps, ejected back into the intergalactic medium. Tracing that evolutionary history is difficult, since gas passes through many different phases, some of which are easier to detect than others. During accretion and, probably, subsequent recycling, the gas is expected to be 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 z>1 QSOs that lie at small angular separations from SDSS galaxies at redshifts between z=0.15 and 0.35. 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 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 12163: Structure and Stellar Content of the Nearest Nuclear Clusters in Late-Type Spiral Galaxies

the nearby spiral, NGC 300, one of the galaxies targetted in this program Extensive observations over the past decade, primarily with HST, have shown that massive, young star clusters are present in the nuclear regions of almost all late-type spiral galaxies. It remains unclear, however, whether those clusters harbour (or generate) the black holes that are commonly found in the central regions of both ellipticals and spiral galaxies with significant bulge components, such as our Milky Way. The present program aims to address this issue through systematic observations of 10 relatively nearby bulgeless spirals. The aim is to combine multi-wavelength, high resolution imaging, using WFC3 on HST, with ground-based spectroscopy of the central regions of these systems. The resultant detailed colour-magnitude diagrams and spectral line strengths will be used in conjunction with stellar population models to constrain the star formation history and stellar content of the central regions, while the kinematics will probe the dynamics of the central regions, and set limits on the likely presence of central black holes in these systems.

GO 12165: Characterizing the UV environment of GJ1214b

Artist's impression of the GJ 1214 system The first exoplanet, 51 Peg b, was discovered through radial velocity measurements in 1995. 51 Pegb was followed by a trickle, and then a flood of other discoveries, as astronomers realised that there were other solar systems radically different from our own, where "hot jupiters" led to short-period, high-amplitude velocity variations. Then, in 1999, came the inevitable discovery that one of those hot jupiters. HD 209458b, was in an orbit aligned with our line of sight to the star, resulting in transits. Since that date, the number of known transiting exoplanet systems has grown to more than 100 from ground-based observations, most detected through wide-field photometric surveys, while the high-sensitivity data provided by Kepler has added a further 1000+ systems. One of the most interesting is the nearby red dwarf star, GJ 1214, which has a transiting ~6.5 Earth-mass companion (a "super-Earth") in an orbit with period 1.58 days, semi-major axis 0.014 AU. At such small separations, the planetary atmosphere is vulnerable to evaporation from high energy radiation from the parent star. In the case of GJ 1214, the primary is a relatively cool mid-type M dwarf, spectral type M4.5, mass ~0.2 solar masses and temperature ~3000K. However, such stars can be subject to significant flare activity. The present HST program aims to quantify GJ 1214's characteristics in that regard throuhg UV spectrosocpy with the Space Telescope Imaging Spectrograph (STIS).

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