This week on HST


HST Programs: May 12 - May 18, 2014

Program Number Principal Investigator Program Title
12969 Peter Garnavich, University of Notre Dame Global Properties Are Not Enough: Probing the Local Environments of Type Ia Supernovae
13024 John S. Mulchaey, Carnegie Institution of Washington A Public Snapshot Survey of Galaxies Associated with O VI and Ne VIII Absorbers
13297 Giampaolo Piotto, Universita degli Studi di Padova The HST Legacy Survey of Galactic Globular Clusters: Shedding UV Light on Their Populations and Formation
13301 J. Michael Shull, University of Colorado at Boulder Deep COS Spectra of the Two Brightest Quasars that Probe the He II Post-Reionization Era
13308 Ming Zhao, The Pennsylvania State University Near-IR spectroscopy of the highly inflated, hottest known Jupiter KOI-13.01
13309 Yicheng Guo, University of California - Santa Cruz UV Snapshot of Low-redshift Massive Star-forming Galaxies: Searching for the Analogs of High-redshift Clumpy Galaxies
13325 Claus Leitherer, Space Telescope Science Institute Pushing COS to the {Lyman-}Limit
13330 Bradley M Peterson, The Ohio State University Mapping the AGN Broad Line Region by Reverberation
13352 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time
13386 Steven A. Rodney, The Johns Hopkins University Frontier Field Supernova Search
13412 Tim Schrabback, Universitat Bonn, Argelander Institute for Astronomy An ACS Snapshot Survey of the Most Massive Distant Galaxy Clusters in the South Pole Telescope Sunyaev-Zel'dovich Survey
13420 Guillermo Barro, University of California - Santa Cruz The progenitors of quiescent galaxies at z~2: precision ages and star-formation histories from WFC3/IR spectroscopy
13455 John Krist, Jet Propulsion Laboratory The Eccentric Debris Ring Around HD 202628: Signs of Planetary Perturbations
13457 Kailash C. Sahu, Space Telescope Science Institute Accurate Mass Determination of the Nearby Old White Dwarf Stein 2051B through Astrometric Microlensing
13470 Julio Chaname, Pontificia Universidad Catolica de Chile Probing Cold Dark Matter Substructure with Wide Binaries in Dwarf Spheroidal Galaxies
13491 Todd Tripp, University of Massachusetts - Amherst Directly Probing >10^6 K Gas in Lyman Limit Absorbers at z > 2
13503 Britney E. Schmidt, Georgia Institute of Technology Searching for Satellites of Ceres: Support for the Dawn Mission
13513 Julia Comerford, University of Colorado at Boulder A Pilot Search for Spatially Offset AGN in Galaxy Merger Remnants
13614 Joaquin Vieira, University of Illinois at Urbana - Champaign High-Redshift Starburst Galaxies Under the Cosmic Microscope: Unveiling the stellar histories of strongly lensed starburst galaxies
13620 William B. Sparks, Space Telescope Science Institute Probing the atmosphere of a transiting ocean world: are there ice fountains on Europa?
13626 Arlin Crotts, Columbia University in the City of New York Light Echoes and Environment of SN 2014J in M82

Selected highlights

GO 13301: Deep COS Spectra of the Two Brightest Quasars that Probe the He II Post-Reionization Era


an HST GHRS spectrum of the bright quasar, HE 2347-4342
In astronomy, 'reionisation" usually refers to the period in the early universe (6 < z < 10) when star formation and/or accreting supermassive black holes produced sufficient ultraviolet flux to ionise hydrogen and lift the veil of the cosmic dark ages. However, intergalactic helium remained neutral at that time. The reionisation epoch for intergalactic helium is thought to occur somewhere between redshifts 3 and 4. Tracking the onset of that epoch through analysis of the He II Lyman alpha absorption constrains the evolution of star formation in the univers at those epochs. Observations, however, are complicated by the continued presence of neutral hydrogen, which absorbs radiaton at those wavelengths. The present program is using the Cosmic Origins Spectrograph to obtain deep observations of two of the brightest known He II quasars, HE2347-4342 and HS1700+6416. Both have previous UV spectroscopic observations by HST, as witnessed by the GHRS spectrum, but the new COS observations will be orders of magnitude more sensitive and can resolve individual He II absorption lines for comparison with neutral hydrogen and metal lines (C IV, Si IV). Inded, these observations will set a new benchmark for QSO absorption line studies with COS.

GO 13352: WISP - A Survey of Star Formation Across Cosmic Time


A region of massive star formation
Star formation is the key astrophysical process in determining the overall evolution of galactic systems, the generation of heavy elements, and the overall enrichment of interstellar and intergalactic material. Tracing the overall evolution through a wide redshift range is crucial to understanding how gas and stars evolved to form the galaxies that we see around us now. The present program builds on the ability of HST to carry out parallel observations, using more than one instrument. While the Cosmic Origins Spectrograph is focused on obtaining ultraviolet spectra of unparalleled signal-to-noise, this program uses the near-infrared grisms mounted on the Wide-Field Camera 3 infrared channel to obtain low resolution spectra between 1 and 1.6 microns of randomly-selected nearby fields. The goal is to search for emission lines characteristic of star-forming regions. In particular, these observations are capable of detecting Lyman-alpha emission generated by star formation at redshifts z > 5.6. A total of up to 40 "deep" (4-5 orbit) and 20 "shallow" (2-3 orbit) fields will be targeted in the course of this observing campaign.

GO 13503: Searching for Satellites of Ceres: Support for the Dawn Mission

HST images of the dwarf planet, Ceres Ceres is one of the largest members of the main belt asteroids. Indeed, Ceres was the first such object discovered, by Giuseppe Piazzi in the coruse of his 1801 survey for a new planet that might fill out the Titius-Bode numerical sequence. Roughly spherical, with a diameter of 950 km, Ceres has been studied extensively from both ground and space. It is also targeted for study by NASA's DAWN mission, launched on September 27 2007. Dawn previously encountered the asteroid Vesta in August 2011, mapping the surface from a low altitude orbit which it maintained through September 5 2012. At that point the spacecraft used its xenon-ion engine to leave orbit and head for Ceres, where it is expected to arrive in March or April 2015. Dawn's observations of Vesta reveal a highly cratered surface, together with dark features that are believed to have originated in past impact events. Ceres is currently at opposition, and the present program aims to use deep WFC3 imaging to search for very low mass companions ("moons"), whose presence would be of significance in planning the details of the DAWN's final encounter.

GO 13626: Light Echoes and Environment of SN 2014J in M82


Image of the recent supernova in M82, Jan 24th (Katzman Automated Imaging Telescope/LOSS)
Type Ia supernovae are generally believed to be produced by the explosive deflagration of white dwarf star that exceeds the Chandrasekhar due to accretion from a binary companion, either a hydrogen-burning main-sequence/red giant star or another degenerate. Besides providing crucial information on stellar evolution and how stars enrich the interstellar medium, Type Ia supernovae have acquired global importance in recent years through their use as distance indicators. Indeed, these objects played a crucial role in identifying dark energy and the accelerating universe. In that context, it is important to understand the distribution of intrinsic properties of these exploding stars, and whether those properties, particularly lumunisuty, correlate with other parameters, such as metallicity. Relatively nearby supernovae that can be probed in detail are therefore crucial to the large mapping of the cosmic flow. Astronomers were therefore delighted with the discovery of a type Ia supernova in the relatively nearby starburst galaxy, M82 (d~3.5 Mpc). This object, designated SN2014J, was discovered on January 21st by a group of UCL undergraduates and their lecturer in a series of short exposures taken as a quick test as clouds closed in on London's Mill Hill Observatory. The supernoa reached maximum at V~10.5 in early February and has since declined to fainter than 14th magnitude at visual wavelengths. The current program aims to probe the immediate environments of the supernova by searching for evidence of light echoes - reflections of the original explosion produced by interstellar features in the vicinity of the supernova.

Past weeks:
page by Neill Reid, updated 18/5/2014
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