This week on HST

HST Programs: December 15 - December 21 , 2014

Program Number Principal Investigator Program Title
13342 Q. Daniel Wang, University of Massachusetts - Amherst WARM AND HOT GASES IN AND AROUND CLUSTER GALAXIES AT Z=0.1-0.2
13352 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time
13395 Theodore R. Gull, NASA Goddard Space Flight Center Constraining the evolutionary state of the hot, massive companion star and the wind-wind collision region in Eta Carinae
13483 Goeran Oestlin, Stockholm University eLARS - extending the Lyman Alpha Reference Sample
13504 Jennifer Lotz, Space Telescope Science Institute HST Frontier Fields - Observations of MACSJ1149.5+2223
13643 Gaspard Duchene, University of California - Berkeley Imaging the tenuous dusty atmosphere of edge-on protoplanetary disks
13646 Ryan Foley, University of Illinois at Urbana - Champaign Understanding the Progenitor Systems, Explosion Mechanisms, and Cosmological Utility of Type Ia Supernovae
13654 Matthew Hayes, Stockholm University Ultraviolet Spectroscopy of the Extended Lyman Alpha Reference Sample
13661 Matthew Auger, University of Cambridge A SHARP View of the Structure and Evolution of Normal and Compact Early-type Galaxies
13665 Bjoern Benneke, California Institute of Technology Exploring the Diversity of Exoplanet Atmospheres in the Super-Earth Regime
13669 Marcella Carollo, Eidgenossiche Technische Hochschule (ETH) The star-formation histories within clumpy disks at z ~ 2.2
13677 Saul Perlmutter, University of California - Berkeley See Change: Testing time-varying dark energy with z>1 supernovae and their massive cluster hosts
13679 Lorenz Roth, Royal Institute of Technology Europa's Water Vapor Plumes: Systematically Constraining their Abundance and Variability
13691 Wendy L. Freedman, University of Chicago CHP-II: The Carnegie Hubble Program to Measure Ho to 3% Using Population II
13695 Benne W. Holwerda, Sterrewacht Leiden STarlight Absorption Reduction through a Survey of Multiple Occulting Galaxies (STARSMOG)
13704 Steven G. Parsons, Valparaiso University Testing the single degenerate channel for supernova Ia
13715 Jennifer Sokoloski, Columbia University in the City of New York Imaging Spectroscopy of the Gamma-Ray Nova V959 Mon
13729 Andy Lawrence, University of Edinburgh, Institute for Astronomy Slow-blue PanSTARRS transients : high amplification microlens events?
13741 Thaisa Storchi-Bergmann, Universidade Federal do Rio Grande do Sul Constraining the structure of the Narrow-Line Region of nearby QSO2s
13752 John Henry Debes, Space Telescope Science Institute An autopsy of dead planetary systems with COS
13760 Derck L. Massa, Space Science Institute Filling the gap --near UV, optical and near IR extinction
13761 Stephan Robert McCandliss, The Johns Hopkins University High efficiency SNAP survey for Lyman alpha emitters at low redshift
13767 Michele Trenti, University of Cambridge Bright Galaxies at Hubble's Detection Frontier: The redshift z~9-10 BoRG pure-parallel survey
13776 Michael D. Gregg, University of California - Davis Completing The Next Generation Spectral Library
13790 Steven A. Rodney, The Johns Hopkins University Frontier Field Supernova Search
13799 Or Graur, New York University Constraining Type Ia Supernova Nucleosynthesis and Explosion Models Using Late-Time Photometry of SN2012cg
13833 Nicolas Tejos, University of California - Santa Cruz Characterizing the cool and warm-hot intergalactic medium in clusters at z < 0.4
13834 Roeland P. van der Marel, Space Telescope Science Institute The Proper Motion Field along the Magellanic Bridge: a New Probe of the LMC-SMC interaction
13845 Adam Muzzin, Sterrewacht Leiden Resolved H-alpha Maps of Star-forming Galaxies in Distant Clusters: Towards a Physical Model of Satellite Galaxy Quenching
13872 Pascal Oesch, Yale University The GOODS UV Legacy Fields: A Full Census of Faint Star-Forming Galaxies at z~0.5-2
13948 Cristian Saez, University of Maryland CONSTRAINING THE WIND-SHIELD SCENARIO OF PG 2112+059
14040 David Jewitt, University of California - Los Angeles Unique Hubble Investigation of a Newly Discovered Main Belt Comet

Selected highlights

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 13504: HST Frontier Fields - Observations of MACSJ1149.5+2223

The Frontier Fields cluster, MACSJ1149.5+2223
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 builds on the highly successful CLASH program,which used 17-colour ACS/WFC3 images to map 25 galaxy clusters, tracing the mas profile and the dark matter distribution. in addition, the observations identified several lensed galaxies at redshifts that enter the JWST domaine, with the most distant object lying at a redshift z~11, within a few hundred million years of the Big Bang. The Frontier Fields program is a large-scale Director's Discretionary program that capitalises on the latter characteristic by targeting 4-6 strong-lensing galaxy clusters for very deep optical and near-infrared imaging. WFC3 and ACS will be used to observe the clusters, with simultaneous imaging obtained in parallel of a nearby "blank" field. Since the observations need to made at a specific orientation, they are being taken in two sets, ~6 months apart, alternating between detectors. MACSJ1149.5+2223 at z=0.544 is the fourth target: at this first epoch of observation, the cluster is being imaged with WFC3-IR, with ACS being used to obtain optical data on the nearby blank field; the second epoch observations switch cameras, with ACS on the cluster and WFC3-IR on the parallel field.

GO 13665: Exploring the Diversity of Exoplanet Atmospheres in the Super-Earth Regime

Artist's impression of the GJ 1214 system
The first exoplanet, 51 Peg b, was discovered through radial velocity measurements in 1995. 51 Pegb was followed by a trickle, and then a flood of other discoveries, as astronomers realised that there were other solar systems radically different from our own, where "hot jupiters" led to short-period, high-amplitude velocity variations. Then, in 1999, came the inevitable discovery that one of those hot jupiters. HD 209458b, was in an orbit aligned with our line of sight to the star, resulting in transits. Since that date, the number of known transiting exoplanet systems has grown to more than 100 from ground-based observations, most detected through wide-field photometric surveys, while the high-sensitivity data provided by Kepler has added a further 1000+ confirmed systems and ~2000 additional candidates. With the added numbers, observations have pushed detections to lower and lower masses, and it is now clear that the most common type of planet is the "super-Earth" - planets with masses that are several (3-6) times that of Earth and radii 2-4 times larger than Earth. One of the earliest examples is the planet circling the M dwarf, GJ 1214. Such planets have no obvious analogue in the Solar System, and the measured masses and diameters might reflect a range of interior structurees: large rocky bodies with relatively thin atmospheres; dense cores surrounded by a steam atmosphere; or "mini-Neptunes", with rock or ice cores surrounded by extended hydrogen or helium atmospheres. The present program aims to probe the diversity of these systems by using the G141 grism on Wide-Field Camera 3 to obtain time-resolved scanning observations of five transiting systems. The goal is to obtain data that will clearky distinguish between large scaleheight, hydrogen-dominated atmospheres and a more compact, steam-dominated systems.

GO 13679: Europa's Water Vapor Plumes: Systematically Constraining their Abundance and Variability

The HST imaging of a potential water plume around Europa's south pole superimposed on an image of the satellite
Europa is the smallest, and the most intriguing, of the four Galilean satellites of Jupiter. With a diameter of 3139 km, Europa is almost twice the size of Earth's moon and significantly larger than Mercury. In 1957, Gerard Kuiper commented that both infrared spectroscopy and the optical colours and albedo suggested that Jovian satellite II (Europa) is covered "by H2O snow". Images taken by the Voyager space probes in the late 1970s (see left) reveal a smooth surface, with only a handful of craters larger than a few kilometres. These features are consistent with a relatively young, icy surface. Subsequent detailed investigations by the Galileo satellite strongly suggest that a substantial body of liquid water, heated by tidal friction, underlies a 5 to 50 km thick icy crust. The presence of this subterranean (subglacial?) ocean clearly makes Europa one of the two most interesting astrobiology targets in the Solar System. Most recently, analysis of observations taken by the Space Telescope imaging Spectrograph (STIS) on Hubble indicated the presence of an extended cloud of Lyman-alpha emission near the polar regions while Europa was furthest in its orbit from Jupiter, strongly suggesting that Europa's oceans may be vaporising into space.Follow-up observations on two further occasions earlier in 2014 failed to detect any emission, suggesting that the emission is either sporadic or periodic; in the latter case, the emission might be related to the location of Europa within its orbit and the consequent tidal strain imposed by Jupiter. The present program aims to address this question through a methodical series of observatons designed to image Europa at a progressive series of orbital locations. The program uses STIS to search for H and O auroral emissions at UV wavelengths\ and will aim to map the distribution of emission at different phases of the Europan orbit..

Past weeks:
page by Neill Reid, updated 11/11/2014
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