HST this week: 182



This week on HST


HST Programs: July 1 - July 7, 2013

Program Number Principal Investigator Program Title
12870 Boris T. Gaensicke, The University of Warwick The mass and temperature distribution of accreting white dwarfs
12873 Beth Biller, Max-Planck-Institut fur Astronomie, Heidelberg Search for Planetary Mass Companions around the Coolest Brown Dwarfs
12880 Adam Riess, The Johns Hopkins University The Hubble Constant: Completing HST's Legacy with WFC3
12881 Peter McCullough, Space Telescope Science Institute Spanning the chasms: re-observing the transiting exoplanet HD 189733b
12884 Harald Ebeling, University of Hawaii A Snapshot Survey of The Most Massive Clusters of Galaxies
12898 Leon Koopmans, Kapteyn Astronomical Institute Discovering the Dark Side of CDM Substructure
12902 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time
12913 Saurabh W. Jha, Rutgers the State University of New Jersey The Peculiar Type Ia Supernova 2012Z: A Massive Star Progenitor?
12925 Andrew A. Cole, University of Tasmania Splendid Isolation: Using DDO 210 to Benchmark Dwarf Galaxy Evolution
12936 Edward B. Jenkins, Princeton University The Physical and Dynamical Properties of Gas that Molds the Fermi Bubbles
12942 Eilat Glikman, Yale University Testing the Merger Hypothesis for Black Hole/Galaxy Co-Evolution at z~2
12949 Daniel Perley, California Institute of Technology Unveiling the Dusty Universe with the Host Galaxies of Obscured GRBs
12964 Marina Rejkuba, European Southern Observatory - Germany Probing the outermost halo in a giant galaxy: is it metal-poor and where does it end?
12967 Abhijit Saha, National Optical Astronomy Observatory, AURA Establishing a Network of DA White Dwarf SED Standards
12970 Michael C. Cushing, University of Toledo Completing the Census of Ultracool Brown Dwarfs in the Solar Neighborhood using HST/WFC3
12973 Curtis McCully, Rutgers the State University of New Jersey UV Spectroscopy of a Peculiar White Dwarf Supernova
12977 Ivana Damjanov, Smithsonian Institution Astrophysical Observatory Local Turbulent Disks: analogs of high-redshift vigorously star-forming disks and laboratories for galaxy assembly?
12982 Nicolas Lehner, University of Notre Dame Are the Milky Way's High Velocity Clouds Fuel for Star Formation or for the Galactic Corona?
12996 Christopher Johns-Krull, Rice University Exploring the Role of Stellar Magnetic Fields in Accretion and Outflows from Young Stars using the Hot Emission Lines of Herbig Ae/Be Stars
13003 Michael D. Gladders, University of Chicago Resolving the Star Formation in Distant Galaxies
13020 Edward F. Guinan, Villanova University A Comprehensive COS Study of the Magnetic Dynamos, Rotations, UV Irradiances and Habitability of dM Stars with a Broad Span of Ages
13024 John S. Mulchaey, Carnegie Institution of Washington A Public Snapshot Survey of Galaxies Associated with O VI and Ne VIII Absorbers
13025 Andrew J. Levan, The University of Warwick Unveiling the progenitors of the most luminous supernovae
13030 Alex V. Filippenko, University of California - Berkeley Early Time UV Spectroscopy of a Stripped-Envelope Supernova: A New Window
13046 Robert P. Kirshner, Harvard University RAISIN: Tracers of cosmic expansion with SN IA in the IR
13050 Remco van den Bosch, Max-Planck-Institut fur Astronomie, Heidelberg The Most Massive Black Holes in Small Galaxies
13063 Adam Riess, The Johns Hopkins University Supernova Follow-up for MCT
13176 Daniel Apai, University of Arizona Extrasolar Storms: The Physics and Chemistry of Evolving Cloud Structures in Brown Dwarf Atmospheres
13400 Arlin Crotts, Columbia University in the City of New York The Surprising Ejecta Geometry of Recurrent Nova T Pyx

Selected highlights

GO 12881: Spanning the chasms: re-observing the transiting exoplanet HD 189733b


Key events in a planetary transit
HD 198733 is a 7th magnitude G5 dwarf that lies at a distance of ~20 parsecs from the Sun in the constellation of Vulpecula. Like many other nearby solar-type stars, HD 189733 has an associated planetary system, including a hot Jupiter, a ~1.15 MJ gas giant with an orbital period of 2.12 days. Most significantly, that inner planet transits the central star, making HD 189733 the closest transiting system found so far. Transiting systems offer a potential gold-mine for extrasolar planetary studies, since not only is the orbital inclination well defined, but the diameter (and hence the average density) is directly measureable form the eclipse depth, while the atmospheric composition can be probed through line absorption or re-radiated thermal flux. The results from these measurments can be used to test, and improve, theoretical models of extrasolar planets. These observations are best done from space: indeed, the only successful atmospheric observations to date have been with HST and Spitzer. HD 189733 has been one of the kost popular targets, with previous observations used to measure the diameter (GO 10923: ACS/HRC in Cycle 15), search for atmospheric water (GO 11117: NICMOS, Cycle 16; GO 11740, STIS & WFC3/IR, Cycle 17) and sodium (GO 11572: STIS, Cycle 17), and probe the outer atmospheric dynamics (GO 11572: STIS, Cycle 17). The results are somewhat controversial, with alternative ijnterpretation of the NICMOS and (shorter-wavelength) WFC3-IR data. The present prorgam aims to resolve those controversies by obtaing new WFC3-IR G141 data that span the gap between the older WFC3-IR and NICMOS observations.

GO 12942: Testing the Merger Hypothesis for Black Hole/Galaxy Co-Evolution at z~2


Composite optical/radio image of Cen A, the elliptical merger that harbours the nearest AGN
Quasars are highly energetic sources that can achieve luminosities substantially exceeding 1012 LSun. These objects are generally believed to be powered by accretion onto a central supermassive black hole, with M > 107 MSun. Many QSOs reside within galaxies that are morphologically similar to elliptical galaxies, which are predominantly gas poor at the present epoch. This raises the issue of how one fuels the central, active black hole. One possibility is through mergers, with the QSO host assimilating gas-rich neighbours. The persent program aims to test this hypothesis through observations of luminous, dusty QSOs at redshifts z>2. The targets were selected by cross-referencing the FIRST radio catalogue with 2MASS near-IR survey data, combined with follow-up spectroscopic confirmation of the nature of the sources. The goal of this program is to use near-infrared imaging with the WFC3-IR camera to search for morphological evidence of merging systems that coudl power the central black hole.

GO 12949: Unveiling the Dusty Universe with the Host Galaxies of Obscured GRBs


Artist's impression of a gamma-ray burst
Gamma ray bursts are events that tap extraordinary energies (1045 to 1047 joules) in remarkably short periods of time. Several thousands bursts have been detected over the last 30+ years, and analyses indicate that they can be divided into two classes with durations longer or shorter than 2 seconds. The short bursts appear to release more high energy radiation, so the two subsets are known as long/soft and short/hard bursts.The short/hard bursts appear to arise from coalescing binary systems (probably pairs of neutron stars or black holes), but the long/soft bursts appear to originate in the collapse of very massive stars. The latter sources are therefore almost certainly associated with star formation, so they act as signposts to active star-forming regions in the high redshift universe. Recent observations have revealed the presence of a subset of highly-obscured long-duration GRBs, which are believed to be associated with galaxies that are both significantly more metal-rich and dustier than the canonical long-duration GRB hosts. The present program aims to combine HST and Spitzer measurements of a sample of 18 such objects, obtaining deep images with the WFC3-IR camera in the F160W filter, potentially supplemented by data in F105W, F110W or F125W, to add to the Spitzer mid-IR imaging. The goal is to better understand the environment and stellar populations in these dusty host galaxies.

GO 12964: Probing the outermost halo in a giant galaxy: is it metal-poor and where does it end?


High contrast imaging of Centaurus A, from ground-based imaging with the CTIO 4-metre Blanco telescope
Centaurus A, or NGC 5128, lies at a distance of 3-5 Mpc from the Milky Way. Originally catalogued in 1826, it is a compelx system, generally agreed to comprise a large elliptical undergoing a merger with a less massive gas-rich system. As noted elsewhere, the galaxy has a massive central black hole, leading its having strong radio emission (hence the name Cen A), and its characterisation as the nearest AGN. The merging galaxy contributes an extensive band of star formation along the central axis of the system. The present program focuses on stars at larger radii, within a postulated extended halo. HST has undertaken observations of stars within the halo populations of other nearby galaxies, notably the Andromeda spiral and galaxies in the Virgo cluster, with a range of results regarding the underlying metallicity distribution. These observations aim to use AFC3 and ACS to obtain deep, multicolour observations in several fields at distances of more than 10 times the effective radius of the system, probing the metallicity distribution of the halo in this complex system.

Past weeks:
page by Neill Reid, updated 14/10/2012
These pages are produced and updated on a best effort basis. Consequently, there may be periods when significant lags develop. we apologise in advance for any inconvenience to the reader.

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