This week on HST

HST Programs: July 25, 2011 - July 31, 2011

Program Number Principal Investigator Program Title
11598 Jason Tumlinson, Space Telescope Science Institute How Galaxies Acquire their Gas: A Map of Multiphase Accretion and Feedback in Gaseous Galaxy Halos
12027 James C. Green, University of Colorado at Boulder COS-GTO: STAR FORMATION/LYMAN-ALPHA Part 2
12059 Julianne Dalcanton, University of Washington A Panchromatic Hubble Andromeda Treasury - I
12062 Sandra M. Faber, University of California - Santa Cruz Galaxy Assembly and the Evolution of Structure over the First Third of Cosmic Time - III
12075 Julianne Dalcanton, University of Washington A Panchromatic Hubble Andromeda Treasury - I
12166 Harald Ebeling, University of Hawaii A Snapshot Survey of The Most Massive Clusters of Galaxies
12185 Jenny E. Greene, University of Texas at Austin The Hosts of Megamaser Disk Galaxies
12191 James T. Lauroesch, University of Louisville Research Foundation, Inc. Prospecting for Rare Elements in the Interstellar Medium
12192 James T. Lauroesch, University of Louisville Research Foundation, Inc. A SNAPSHOT Survey of Interstellar Absorption Lines
12200 Gregory James Schwarz, American Astronomical Society STIS UV spectroscopy of a bright classical nova during its super soft X-ray phase
12206 Mark S. Westmoquette, European Southern Observatory - Germany Starburst-driven shocks and feedback in the near-IR at high resolution
12209 Adam S. Bolton, University of Utah A Strong Lensing Measurement of the Evolution of Mass Structure in Giant Elliptical Galaxies
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?
12215 Nancy R. Evans, Smithsonian Institution Astrophysical Observatory Searching for the Missing Low-Mass Companions of Massive Stars
12228 Glenn Schneider, University of Arizona Probing for Exoplanets Hiding in Dusty Debris Disks: Inner {<10 AU} Disk Imaging, Characterization, and Exploration
12234 Wesley Fraser, California Institute of Technology Differentiation in the Kuiper belt: a search for silicates on icy bodies.
12238 William E. Harris, McMaster University Supermassive Star Clusters in Supergiant Galaxies: Tracing the Enrichment of the Earliest Stellar Systems
12253 Douglas Clowe, Ohio University Gravity in the Crossfire: Revealing the Properties of Dark Matter in Bullet-like Clusters
12255 Trent J. Dupuy, Smithsonian Institution Astrophysical Observatory Probing Ultracool Atmospheres and Substellar Interiors with Dynamical Masses
12260 Roderick M. Johnstone, University of Cambridge Probing Intermediate Ionization Gas in the Perseus and Virgo Clusters
12269 Claudia Scarlata, University of Minnesota - Twin Cities The escape of Lya photons in star-forming galaxies
12275 Bart P. Wakker, University of Wisconsin - Madison Measuring gas flow rates in the Milky Way
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
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
12683 P. Frank Winkler, Middlebury College Estimating the Black Hole Mass in the New UltraLuminous X-ray Source in M83

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 12060/12062: CANDELS: Galaxy Assembly and the Evolution of Structure over the First Third of Cosmic Time

Part of the GOODS/Chandra Deep Field South field, as imaged by HST CANDELS is one of three Multi-Cycle Treasury Program, whose observations will be executed over the next three HST Cycles. It builds on past investment of both space- and ground-based observational resources. In particular, it includes coverage of the two fields of the Great Observatory Origins Deep Survey (GOODS), centred on the northern Hubble Deep Field (HDF) in Ursa Major and the Chandra Deep Field-South in Fornax. In addition to deep HST data at optical and near-infrared wavelengths, the fields have been covered at X-ray wavelengths by Chandra (obviously) and XMM-Newton; at mid-infrared wavelengths with Spitzer; and ground-based imaging and spectroscopy using numerous telescopes, including the Kecks, Surbaru and the ESO VLT. This represents an accumulation of almost 1,000 orbits of HST time, and comparable scale allocations on Chandra, Spitzer and ground-based facilities. The CANDELS program is capitalising on this large investment, with new observations with WFC3 and ACS on both GOODS fields, and on three other fields within the COSMOS, EGS and UDS survey areas (see this link for more details). The prime aims of the program are twofold: reconstructing the history of galaxy formation, star formation and nuclear galactic activity at redshifts between z=8 and z=1.5; and searching for high-redshift supernovae to measure their properties at redshifts between z~1 and z~2. The program incorporates a tiered set of observations that complement, in areal coverage and depth, the deep UDF observations, while the timing of individual observations will be set to permit detection of high redshift SNe candidates for subsequent follow-up.

GO 12255: Probing Ultracool Atmospheres and Substellar Interiors with Dynamical Masses

NICMOS images of the ultracool L/T binary, 2MASS J22521073-1730134; the northern component, notably fainter at F160W, is the T dwarf. Brown dwarfs are objects that form like stars, but lack sufficient mass to drive the central temperature above a few million degrees, and therefore never succeed in igniting core hydrogen fusion. Discovered in the early- to mid-1990s (although predicted theoretically since the early 1960s), these objects initially have surface temperatures of ~3,500K, but cool rapidly and move through spcetral types M, L and T. Following their discovery, considerable theoretical attention has focused on the evolution of their intrinsic properties, particularly the details of the atmospheric changes in the evolution from type L to type T and beyond. The overall timescales associated with this process remains unclear. Mass is a crucial factor in mapping those changes, but mass is also the most difficult quantity to measure in a reliable fashion. The present program aims to tackle this issue through observations of low-mass binary systems. Previous observing programs have been used to measure astrometric orbits, and hence derive dynamical masses. The present program aims to use STIS to obtain optical spectra of each component in three binary systems. The data will cover the Li 6708 A absorption feature, whose presence is a key age indicator.

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