This week on HST


HST Programs: November 5 - November 11, 2012

Program Number Principal Investigator Program Title
12025 James C. Green, University of Colorado at Boulder COS-GTO: QSO Absorbers, Galaxies and Large-scale Structures in the Local Universe Part 2
12444 Sandra M. Faber, University of California - Santa Cruz Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey -- GOODS-North Field, Middle Visits of SNe Search
12471 Dawn K. Erb, University of Wisconsin - Milwaukee The Bottom of the Iceberg: Faint z~2 Galaxies and the Enrichment of the IGM
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
12559 Justyn R. Maund, University of Copenhagen, Niels Bohr Institute Stellar Forensics III: A post-explosion view of the progenitors of core-collapse supernovae
12568 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time
12587 Miriam Garcia, Instituto de Astrofisica de Canarias Winds of very low metallicity OB stars: crossing the frontier of the Magellanic Clouds
12603 Timothy M. Heckman, The Johns Hopkins University Understanding the Gas Cycle in Galaxies: Probing the Circumgalactic Medium
12605 Giampaolo Piotto, Universita degli Studi di Padova Advances in Understanding Multiple Stellar Generations in Globular Clusters
12661 Michael C. Liu, University of Hawaii Dynamical Masses of the Coolest Brown Dwarfs
12685 Dean C. Hines, Space Telescope Science Institute Enabling Dark Energy Science for JWST and Beyond
12812 Zolt Levay, Space Telescope Science Institute Hubble Heritage
12863 Amy Kathryn Furniss, University of California - Santa Cruz Determining the Redshift of the Blazar 3C 66A for Studies of the Extragalactic Background Light
12866 Mark Swinbank, University of Durham A Morphological Study of ALMA Identified Sub-mm Galaxies with HST/WFC3
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
12879 Adam Riess, The Johns Hopkins University A 1% Measurement of the Distance Scale with Perpendicular Spatial Scanning
12891 Keith S. Noll, NASA Goddard Space Flight Center Search For Binaries Among Ultra-Slow Rotating Trojans, Hildas, and Outer Main Belt Asteroids
12902 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time
12903 Luis C. Ho, Carnegie Institution of Washington The Evolutionary Link Between Type 2 and Type 1 Quasars
12927 Andrew B. Newman, California Institute of Technology The role of the environment in the growth of compact red galaxies at z~2
12929 Judith L. Provencal, University of Delaware COS Observations of Pulsating DB White Dwarfs
12930 Carrie Bridge, California Institute of Technology WISE Discovered Ly-alpha Blobs at High-z: The missing link?
12934 Clive N. Tadhunter, University of Sheffield The importance warm outflows in the most rapidly evolving galaxies in the local Universe
12936 Edward B. Jenkins, Princeton University The Physical and Dynamical Properties of Gas that Molds the Fermi Bubbles
12975 Simon J. Lilly, Eidgenossiche Technische Hochschule (ETH) Do winds transport magnetic fields out of high redshift galaxies?
12995 Christopher Johns-Krull, Rice University Testing Disk Locking in the Orion Nebula Cluster
13007 Lee Armus, California Institute of Technology UV Imaging of Luminous Infrared Galaxies in the GOALS Sample
13025 Andrew J. Levan, The University of Warwick Unveiling the progenitors of the most luminous supernovae
13040 Joachim Saur, Universitat zu Koeln Investigation of Emission Anomalies from Europa's Atmosphere: Search for Possible Plumes
13046 Robert P. Kirshner, Harvard University RAISIN: Tracers of cosmic expansion with SN IA in the IR
13102 Michael McDonald, Massachusetts Institute of Technology Zooming in on the Starburst at the Core of the Phoenix Cluster
13113 C. S. Kochanek, The Ohio State University ENERGY DEPENDENT X-RAY MICROLENSING AND THE STRUCTURE OF QUASARS
13179 Robert P. Kirshner, Harvard University Ultraviolet Spectra of the Exceptional SN 2009ip

Selected highlights

GO 12471: The Bottom of the Iceberg: Faint z~2 Galaxies and the Enrichment of the IGM


WFC3 grism imaging of a section of the GOODS-North field
Observations with the Hubble telescope have impacted many science areas, but probably none more so than investigations of galaxy formation and evolution in the high redshift universe. Deep field images, starting with the oroginal HDF and progressing through the HDF-South, GOODS-North and South, the Ultra-Deep Field and the infrared UDF, have been coupled with observations at other wavelengths from space and ground to probe galaxy structure at redshifts extending to z=9 and beyond. Most analyses of galaxy evolution as a function of redshift favour the general conclusion that the global star formation rate peaked at redshifts in the range z=2 to 3. Extensive star formation in proto-galaxies at those redshifts leads to extensive gaseous outflows and strong interactions. The present program aims to build on past research by using the spectroscopic capabilities offered by the WFC3-IR grism to survey fields centred on 15 high-redshift QSOs whose spectra have been used to probe the line-of-sight structure of the intergalactic medium. The grism observations will permit dientification of fainter galaxies that may be associated with the strong absorbers detected in the QSO spectra.

GO 12870: The mass and temperature distribution of accreting white dwarfs


An accreting white dwarf starn in a close binary system
Supernovae are the most spectacular form of stellar obituary. Since B2FH, the physical processes underlying their eruptive deaths have been known to play a key role in populating the ISM with metals beyond the iron peak. More recently, these celestial explosions have acquired even greater significance through the use of Type Ia supernovae as distance indicators in mapping the `dark energy' acceleration term of cosmic expansion. However, while there are well-established models for the two main types of supernovae (runaway fusion on the surface of a white dwarf in a binary system for Type Ia, or detonation of the core in Type II), some significant uncertainties remain concerning the physical details of the disruption, and, potentially, the overall uniformity of these events. Consequently, there is potential for systematic bias in the distance estimates. The present program aims to set constraints on the various mechanisms associated with white dwarf stars by investigating the rotational properties of over 40 degenerate companions in catclysimic variable systems. All of these systems are in the process of accreting material from the companion star, as the latter voerflows its Roche lobes. The program aims to obtain ultraviolet spectra with the Cosmic origins Spectrograph, probing both the spin rates and the orbital parameters. Over the next decade, these data may lead to the determinaton of reliable masses for both stars once accurate parallax measurements become available from Gaia.

GO 12891: Search For Binaries Among Ultra-Slow Rotating Trojans, Hildas, and Outer Main Belt Asteroids


Preliminary orbital determination for the KBO WW31, based on C. Veillet's analysis of CFHT observations; the linked image shows the improved orbital derivation, following the addition of HST imaging
The Solar System includes a number of regions occupied by numerous small solid bodies, notably the main asteroid belt, between the orbits of Mars and Jupiter, and the Edgeworth-Kuiper Belt, beyond the orbit of Neptune. More than 96,000 bodies have been catalogued in the former region, including the larger (few hundred km diameter) minor planets like Ceres, Pallas, Juno and Vesta. The main belt asteroids fall into three main categories: carbonaeous (C-type), silicate (S-type) and metal-rich (M-type). A handful of objects have recently been detected showing cometary-like outbursts, suggestive of the presence of volatiles (eg asteroid 596 Scheila); these are classed as "main belt comets". A subset of the main belt asteroids have been captured by Jupiter into orbits that lead or trail Jupiter itself by ~ 60 degrees. these are the Trojan asteroids. The Kuiper Belt consists of icy planetoids that orbit the Sun within a broad band stretching from Neptune's orbit (~30 AU) to distances of ~50 AU from the Sun. Over 500 KBOs (or trans-Neptunian objects, TNOs) are currently known out of a population of perhaps 70,000 objects with diameters exceeding 100 km. The origins of these smaller bodies remains a subject of some debate. In particular, it remains unclear where these bodies formed within the protoplanetary disk. The present proposal aims to probe this question by searching for binary systems among the Outer Main Belt and Trojan asteroids. Once orbits are determined, binary asteroids provide a means of determing the mass, density and hence the composition of these objects. A comparison between the properties of systems in the inner Solar System and in the Kuiper Belt should provide insight on whether a common origin is a reasonable hypothesis.

GO 12929: COS Observations of Pulsating DB White Dwarfs


The surface-temperature map on a pulsating white dwarf (Figure by Mike Montgomery U. Texas group)
White dwarfs are compact, electron-degenerate remnants that represent the final evolutionary stage for stars less massive than ~7 Msun. White dwarfs emerge from planetary nebulae with extremely high surface temperatures, but with no central energy source, they simply cool like a brick. As they cool, the spectral energy distribution and the spectral characteristics evolve with time. Most white dwarfs have thin hydrogen envelopes, and are therefore have strong Balmer-series absorption lines in the optical at temperatures above ~8,000 degrees (DA white dwarfs). A sizeable minority, however, have helium envelopes, and spectra dominated by helium lines; these are DB white dwarfs. Both DA and DB white dwarfs evolve through regions of atmospheric instability as they cool - instability strips, analagous to those populated by Cepheids and RR Lyraes in the hydrogen-burning regime. White dwarfs undergo non-radial pulsations are high-order gravity modes, driven by opacity variations in the stellar interior. In the case of DB white dwarfs, the region falls near surface temperatures of ~19,000K. Determing accurate effective temperatures is crucial to constraining the models developed for these highly compact objects. The present program aims to use UV spectra obtaiend with' the Cosmic Origins Spectrograph to refine temperatures for 6 pulsating DB white dwarfs.

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