This week on HST

HST Programs: December 10 - December 16, 2012

Program Number Principal Investigator Program Title
11622 Heather A. Knutson, California Institute of Technology A Search for Water and Methane on a Neptune-Mass Transiting Planet
12109 Julianne Dalcanton, University of Washington A Panchromatic Hubble Andromeda Treasury - I
12111 Julianne Dalcanton, University of Washington A Panchromatic Hubble Andromeda Treasury - I
12449 Drake Deming, University of Maryland Atmospheric Composition of the ExoNeptune HAT-P-11
12472 Claus Leitherer, Space Telescope Science Institute CCC - The Cosmic Carbon Conundrum
12494 Martin Durant, University of Florida Thermal emission from the famous double pulsar J0737-3039
12533 Crystal Martin, University of California - Santa Barbara Escape of Lyman-Alpha Photons from Dusty Starbursts
12555 Robert Louis da Silva, University of California - Santa Cruz On the Triggering of Quasars During First Passage
12562 Geoffrey C. Clayton, Louisiana State University and A & M College The UV Interstellar Extinction Properties in the Super-Solar Metallicity Galaxy M31
12568 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time
12584 Amy E. Reines, Associated Universities, Inc. Confirming the First Supermassive Black Hole in a Dwarf Starburst Galaxy
12662 Oleg Y. Gnedin, University of Michigan Hypervelocity Stars as Unique Probes of the Galactic Center and Outer Halo
12787 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12788 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12869 Boris T. Gaensicke, The University of Warwick The chemical diversity of extra-solar planetary systems
12870 Boris T. Gaensicke, The University of Warwick The mass and temperature distribution of accreting white dwarfs
12880 Adam Riess, The Johns Hopkins University The Hubble Constant: Completing HST's Legacy with WFC3
12903 Luis C. Ho, Carnegie Institution of Washington The Evolutionary Link Between Type 2 and Type 1 Quasars
12922 Jong-Hak Woo, Seoul National University Calibrating black hole mass estimators using the enlarged sample of reverberation-mapped AGNs
12934 Clive N. Tadhunter, University of Sheffield The importance warm outflows in the most rapidly evolving galaxies in the local Universe
12939 Elena Sabbi, Space Telescope Science Institute - ESA Hubble Tarantula Treasury Project {HTTP: unraveling Tarantula's web}
12940 Philip Massey, Lowell Observatory The Unevolved Massive Star Content of the Magellanic Clouds
12982 Nicolas Lehner, University of Notre Dame Are the Milky Way's High Velocity Clouds Fuel for Star Formation or for the Galactic Corona?
13004 Margaret Meixner, The Johns Hopkins University The Life Cycle of Dust in the Magellanic Clouds: Crucial Constraints from Zn and Cr depletions
13007 Lee Armus, California Institute of Technology UV Imaging of Luminous Infrared Galaxies in the GOALS Sample
13019 Edward F. Guinan, Villanova University Probing the Complicated Atmospheres of Cepheids with HST-COS: Plasma Dynamics, Shock Energetics and Heating Mechanisms
13022 Edo Berger, Harvard University Staring into the Beasts' Lair: HST Observations of the Host Galaxies of Pan-STARRS Ultra-luminous Supernovae
13029 Alex V. Filippenko, University of California - Berkeley A Snapshot Survey of the Sites of Recent, Nearby Supernovae
13033 Jason Tumlinson, Space Telescope Science Institute COS-Halos: New FUV Measurements of Baryons and Metals in the Inner Circumgalactic Medium
13046 Robert P. Kirshner, Harvard University RAISIN: Tracers of cosmic expansion with SN IA in the IR
13118 Michael C Nolan, Universities Space Research Association Lightcurve observations of OSIRIS-REx Sample-Return Mission target 1999 RQ36

Selected highlights

GO 11622: A Search for Water and Methane on a Neptune-Mass Transiting Planet

Artist's impression of the exo-Neptune in orbit around Gliese 436
Gliese 436 is an early-type M dwarf (spectral type M2.5) with a mass approximately 40% that of the Sun lying at a distance of ~10 parsecs. In August 2004, the Lick/Carnegie planet search team (led by Geoff Marcy and Paul Butler) announced the discovery of a ~22 Earth-mass planet in a 2.64 day orbit around this star. Unlike most "hot jupiters", this "hot Neptune" is on an elliptical orbit, e=0.16, which, with a semi-major axis of 0.0278 AU, brings it within 3.5 million kilometres of the central star. Gl 436 is significantly cooler than the Sun, with a surface temperature close to ~3400 degrees Kelvin; even so, the "surface" temperatures on Gl 436b are expected to reach ~740 K (~370 C). In May of this year, a team led by F. Pont demonstrated that Gl 436b transits the parent star. The initial ground-based observations allowed them to derive a diameter approximately 4 times that of Earth, directly comparable with Uranus and Neptune. This provides key insight into the likely origins of Gl 436b, since combining the diameter with the measured mass gives the mean density, and, by inference, the likely composition. For Gl 436b, the indications are that the planet is a displaced "ice giant". Subsequent observations with HST (eg GO 11306) have refined the radius determination. The present program aims to probe the atmospheric structure by using drift-scanning to obtain high signal-to-noise spectra with the WFC3-IR G141 grism. The spectral regions covered (1.3 to 1.7 microns) span several strong absorption bands due to water and methane; differencing the spectra when the system is in and out of transit may lead to detection of significnt atmospheric absorption.

GO 12533: Escape of lyman-Alpha Photons from Dusty Starbursts

HST NICMOS image of the interacting Luminous IR Galaxy, NGC 6090
Ultraluminous infrared galaxies (LIRGs) are systems that are characterised as having luminosities that exceed 1012 LSun, with most of the energy emitted at wavelengths longward of 10 microns. Many (perhaps most) of these galaxies are interacting or merging disk galaxies, with the excess infrared luminosity generated by warm dust associated with the extensive star formation regions. Many systems also exhibit an active nucleus, and may be in the process of evolving towards an S0 or elliptical merger remnant. One of the surprising discoveries in recent years has been the extent to which Lyman-alpha ionising emission can be detected escaping from these dusty systems. The present program looks to quantify the distribution of these properties through COS observations of sixteen ULIRGs in the local universe (z~0.1). These relatively nearby systems can provide insight into the structure of these systems, and give clues to the likely behaviour at higher redshifts.

GO 12788: Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos

The cluster MACS J1206.2-0.47, imaged by HST as part of the CLASH program
The overwhelming majority of galaxies in the universe are found in clusters. As such, these systems offer an important means of tracing the development of large-scale structure through the history of the universe. Moreover, as intense concentrations of mass, galaxy clusters provide highly efficient gravitational lenses, capable of concentrating and magnifying light from background high redshift galaxies to allow detailed spectropic investigations of star formation in the early universe. Hubble imaging has already revealed lensed arcs and detailed sub-structure within a handful of rich clusters. At the same time, the lensing characteristics provide information on the mass distribution within the lensing cluster. The present program aims to capitalise fully on HST's imaging capabilities, utilising the refurbished Advanced Camera for Surveys and the newly-installed Wide-Field Camera 3 to obtain 17-colour imaging of 25 rich clusters. The data will be use to map the mass profiles of the clusters and probe the characteristics of the high-redshift lensed galaxies. Since ACS and WFC3 can be operated in parallel, the program will also use parallel imaging in offset fields to search for high-redshift supernovae. The present observations target the cluster MACS0429-025 at z=0.40.

GO 12940: The Unevolved Massive Star Content of the Magellanic Clouds

Hubble WFC3 imaging of the Tarantula Nebula within 30 Doradus in the Large Magellanic Cloud
The Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC) are the two most massive satellite galaxies in the Milky Way system. The LMC is likely a low-mass irregular spiral system, with mass ~1010 solar masses, while the SMC is an irregular system, mass~few x 109 solar masses. Both are gas-rich, with extensive on-going star formation. In consequence, our external perspective provides an excellent opportunity for probing the star formation process, particularly the formation of massive stars in young clusters, which are frequently difficult to observe within the Milky way itself. Identifying the most massive stars in such systems can be challening, since the spectral energy distribution peaks in then ultraviolet, therefore negating the efficacy of optical photometry as a temperature indicator. The present program will use the WFC3-UVIS camera to obtain short ultraviolet (F225W) images of 23OB associations in the LMC and SMC. Those data will be combined with extensive ground-based imaging to identify the high-termperature O-type stars for subsqequent follow-up spectroscopy.

Past weeks:
page by Neill Reid, updated 14/10/2012
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