This week on HST


HST Programs: Septermber 12, 2011 - September 18, 2011


Program Number Principal Investigator Program Title
11608 Nuria Calvet, University of Michigan How Far Does H2 Go: Constraining FUV Variability in the Gaseous Inner Holes of Protoplanetary Disks
11616 Gregory J. Herczeg, Max-Planck-Institut fur extraterrestrische Physik The Disks, Accretion, and Outflows {DAO} of T Tau stars
12038 James C. Green, University of Colorado at Boulder COS-GTO: COOL, WARM AND HOT GAS IN THE COSMIC WEB AND IN GALAXY HALOS Part 2
12041 James C. Green, University of Colorado at Boulder COS-GTO: Io Atmosphere/STIS
12062 Sandra M. Faber, University of California - Santa Cruz Galaxy Assembly and the Evolution of Structure over the First Third of Cosmic Time - III
12166 Harald Ebeling, University of Hawaii A Snapshot Survey of The Most Massive Clusters of Galaxies
12181 Drake Deming, University of Maryland The Atmospheric Structure of Giant Hot Exoplanets
12188 Jay B. Holberg, University of Arizona Tests of Extreme Physics in Very Cool White Dwarfs
12192 James T. Lauroesch, University of Louisville Research Foundation, Inc. A SNAPSHOT Survey of Interstellar Absorption Lines
12203 S. Adam Stanford, University of California - Davis Rest Frame Optical Spectroscopy of Galaxy Clusters at 1.6 < z < 1.9
12211 Nuria Calvet, University of Michigan Are Weak-Line T Tauri Stars Still Accreting?
12214 Sara Ellison, University of Victoria Low redshift damped Lyman alpha systems selected by 21cm absorption: A new route to high efficiency?
12238 William E. Harris, McMaster University Supermassive Star Clusters in Supergiant Galaxies: Tracing the Enrichment of the Earliest Stellar Systems
12248 Jason Tumlinson, Space Telescope Science Institute How Dwarf Galaxies Got That Way: Mapping Multiphase Gaseous Halos and Galactic Winds Below L*
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
12286 Hao-Jing Yan, University of Missouri - Columbia Hubble Infrared Pure Parallel Imaging Extragalactic Survey {HIPPIES}
12294 Ann M. Boesgaard, University of Hawaii Boron in F stars in the Hyades - Insights into the Li-Be Dip
12298 Richard S. Ellis, California Institute of Technology Towards a Physical Understanding of the Diversity of Type Ia Supernovae
12320 Brian Chaboyer, Dartmouth College The Ages of Globular Clusters and the Population II Distance Scale
12367 Michael R. Garcia, Smithsonian Institution Astrophysical Observatory Monitoring M31 for BHXNe
12370 Andrew S. Fruchter, Space Telescope Science Institute The Astrophysics of the Most Energetic Gamma-Ray Bursts
12514 Karl Stapelfeldt, NASA Goddard Space Flight Center Imaging of Newly-identified Edge-on Protoplanetary Disks in Nearby Star-Forming Regions
12528 Philip Massey, Lowell Observatory Probing the Nature of LBVs in M31 and M33: Blasts from the Past
12679 Adam Riess, The Johns Hopkins University Luminosity-Distance Standards from Gaia and HST
12725 Harold A. Weaver, The Johns Hopkins University Applied Physics Laboratory A Deep Search for Satellites in the Pluto System: Providing Critical, Safety-of-Flight Support to NASA's New Horizons Mission

Selected highlights

GO 11616: The Disks, Accretion, and Outflows (DAO) of T Tau stars


Wide-field image, from NOAO, of T Tauri and its immediate environs
The T Tauri stage of evolution occurs early in a star's lifetime, within ~10 Myrs of its birth, when it still retains a dense, dust and gas-rich circumstellar disk. During this phase, there is substantial accretion of material onto the central star. This leads to heating of the inner regions of the accretion disk, and significant emission at ultraviolet and X-ray wavelengths. Previous HST programs (e.g. GO 10840 ) have used the STIS and the ACS/SBC to investigate these processes at FUV wavelengths. The present program will extend those investigations using COS, which provides more than an order of magnitude more sensitivity and resolution. The survey will target 32 T Tauri stars, including 26 "classical" T Tauris and 6 "weak-lined" T Tauris (the latter are surrounded by less disk material, and are generally believed to be at a later stage of evolution than the CTTs). COS will be used to measure the emission profiles of an extensive number of lines, probing opacities, temperatures and densities in the disk and outflow regions.

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 12248: How Dwarf Galaxies Got That Way: Mapping Multiphase Gaseous Halos and Galactic Winds Below L*


A computer simulation of galactic gas accretion and outflow
Galaxy formation, and star formation within a galaxy, requires the presence of gas. The detailed evolution of individual galactic systems 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 low- to moderate redshift QSOs (0.1 < z < 1) that lie at small angular separations from sub-L* mass galaxies (0.02 < M/L* < 0.3) at redshifts between z=0.01 and 0.06. 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 12725: A Deep Search for Satellites in the Pluto System: Providing Critical, Safety-of-Flight Support to NASA's New Horizons Mission


Hubble Space Telescope images of the Pluto system, including the newly discovered moon, P4
Pluto, one of the largest members of the Kuiper Belt and, until recently, the outermost planet in the solar system, has been in the news over the last year or two. Besides the extended "planet"/"dwarf planet" debate, Pluto is the primary target of the New Horizons Mission. In 1978, James Christy discovered from analyses of photographic plates that Pluto has a relatively large companion moon, Charon, with a diameter of ~1200 km, or almost half that of Pluto itself. In 2005, Hubble observations led to the discovery of two small moons, christened Nix and Hydra. These two new moons are 5,000 fainter than Pluto itself, implying diameters as small as ~30-50 km if the surface composition is similar to Pluto itself. Within the past year, a series of observations were taken in support of the New Horizons mission, using WFC3 to search for faint rings due to dust particles that might jeopardise the space craft and require a course correction. No rings werer detected; however, a fourth small satellite, "P4", was discovered. This object is even fainter than Nix and Hydra, and may well be as small as 13 km in size. The present observations, again in support of new Horizons, will use WFC3 to push to even fainter magnitudes to both better characterise the P4 orbit and search for even fainter moons.

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