This week on HST


HST Programs: May 23 - May 30, 2016

Program Number Principal Investigator Program Title
13760 Derck L. Massa, Space Science Institute Filling the gap --near UV, optical and near IR extinction
14037 Jennifer Lotz, Space Telescope Science Institute HST Frontier Fields - Observations of Abell S1063
14075 Ori Dosovitz Fox, Space Telescope Science Institute Long-Lost Companions: A Search for the Binary Secondaries of Three Nearby Supernovae
14080 Anne Jaskot, Smith College LyC, Ly-alpha, and Low Ions in Green Peas: Diagnostics of Optical Depth, Geometry, and Outflows
14082 Dan Maoz, Tel Aviv University - Wise Observatory Connecting white dwarf rotation and debris accretion
14095 Gabriel Brammer, Space Telescope Science Institute - ESA Calibrating the Dusty Cosmos: Extinction Maps of Nearby Galaxies
14098 Harald Ebeling, University of Hawaii Beyond MACS: A Snapshot Survey of the Most Massive Clusters of Galaxies at z>0.5
14104 Jesus Maiz Apellaniz, Centro de Astrobiologia (CSIC/INTA) Inst. Nac. de Tec. Aero. The optical-UV extinction law in 30 Doradus
14105 Jonathan D. Nichols, University of Leicester Observing Jupiter's FUV auroras near Juno orbit insertion
14119 Luciana C. Bianchi, The Johns Hopkins University Understanding Stellar Evolution of Intermediate-Mass Stars from a New Sample of SiriusB-Like Binaries
14122 Lise Christensen, University of Copenhagen, Niels Bohr Institute Unveiling stellar populations in absorption-selected galaxies
14127 Michele Fumagalli, Durham Univ. First Measurement of the Small Scale Structure of Circumgalactic Gas via Grism Spectra of Close Quasar Pairs
14131 Ivana Orlitova, Astronomical Institute, Academy of Sciences of CR Origin of double peaks in Lyman-alpha spectra: diffuse halos or Lyman continuum leakage?
14134 Swara Ravindranath, Space Telescope Science Institute Spectral Diagnostics for the Reionization Era: Exploring the Semi-Forbidden CIII] Emission in Low Metallicity Green Pea Galaxies
14137 Lorrie Straka, Sterrewacht Leiden Damped Lyman-alpha Systems in the Disks of Low-z SDSS Galaxies on Top of QSOs
14140 Jessica Werk, University of Washington Using UV-bright Milky Way Halo Stars to Probe Star-Formation Driven Winds as a Function of Disk Scale Height
14144 Peter J. Brown, Texas A & M University An Ultraviolet View of Overluminous Type Ia Supernonovae
14161 Ruth C. Peterson, SETI Institute The Intersection of Atomic Physics and Astrophysics: Identifying UV Fe I Lines from Metal-Poor Turnoff Stars
14163 Mickael Rigault, Humboldt Universitat zu Berlin Honing Type Ia Supernovae as Distance Indicators, Exploiting Environmental Bias for H0 and w.
14171 Guangtun Zhu, The Johns Hopkins University Characterizing the Circumgalactic Medium of Luminous Red Galaxies
14178 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey: The WISP Deep Fields
14182 Thomas H. Puzia, Pontificia Universidad Catolica de Chile The Coma Cluster Core Project
14199 Patrick Kelly, University of California - Berkeley Refsdal Redux: Precise Measurements of the Reappearance of the First Supernova with Multiple Resolved Images
14208 Steven A. Rodney, University of South Carolina Research Foundation Frontier Fields Supernova Search
14212 Karl Stapelfeldt, Jet Propulsion Laboratory A Snapshot Imaging Survey of Spitzer-selected Young Stellar Objects in Nearby Star Formation Regions*.t23
14213 Pier-Emmanuel Tremblay, The University of Warwick Defining New IR-Bright Flux Standards for Cosmology Applications
14251 Amy E. Reines, National Optical Astronomy Observatory, AURA The Structures of Dwarf Galaxies Hosting Massive Black Holes
14258 Howard E. Bond, The Pennsylvania State University The Nature of SPIRITS Mid-Infrared Extragalactic Transients
14269 Nicolas Lehner, University of Notre Dame Just the BASICs: Linking Gas Flows in the Circumgalactic Medium to Galaxies
14327 Saul Perlmutter, University of California - Berkeley See Change: Testing time-varying dark energy with z>1 supernovae and their massive cluster hosts
14490 J. Christopher Howk, University of Notre Dame Pop III material found 6 Gyr after the Big Bang? COS constraints on the lowest-metallicity gas at z<1

Selected highlights

GO 14037: HST Frontier Fields - Observations of Abell S1063


The Frontier Fields cluster, Abell S1063
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 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. Abell S1063 at z=0.348 is the fifth target. The first epoch of observation were obtained in late 2015, with the cluster imaged with ACS and WFC3-IR obtaining obtain optical data on the nearby blank field. The second epoch observations, April-June 2016, switch cameras, with ACS on the cluster and WFC3-IR on the parallel field.

GO 14080: LyC, Ly-alpha, and Low Ions in Green Peas: Diagnostics of Optical Depth, Geometry, and Outflows


A montage of green pea galaxies discovered by the Galaxy Zoo project
Understanding the galaxy formation and galaxy evolution has been a strong focus of astronomical research since thne 1970s and remains a key issue for 21st century astrophysics. Since we cannot follow an individual galaxy through time, tackling these questions requires a statistical approach, and, as a result, large-scale surveys have played a crucial role in the field. In particular, the Sloan Digital Sky Survey, conducted from Apache point Observatory from the 1990s through the early years of this century, has provided a treasure trove of information of galaxies at low and moderate redshifts. One of the interesting discoveries that originated from SDSS was the discovery of so-called "green pea" galaxies - compact objects whose combined images have a greenish hue, originally uncovered by citizen scientists as part of the Galaxy Zoo project. Closer inspection shows that these are gas-rich galaxies lying at relatively low redshifts, 0.1 < z < 0.36, with the green-tinged hue partly stemming from the presence of strong oxygen ([O III]) emission. These characteristics indicate that the galaxies are undergoing strong star-forming episodes. The present program aims to take advantage of HST's unparalleled resolution and extraordinary sensitivity at ultraviolet wavelengths, and will use the Cosmic Origins Spectrograph to obtain spectra are far-UV wavelengths. Those observations will probe optical depth, the geometry of neutral gas and radiative transfer within these systems, revealing the physical structure of the underlying star forming regions and potentially offering insight into the nature of high redshift lyman-alpha emitters.

GO 14178: 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 14258: The Nature of SPIRITS Mid-Infrared Extragalactic Transients


NGC 300: the host of a luminous transient source in 2008
Time domaine astronomy has become a growth industry in recent years, with large-scale surveys such as Pan-STARRS and the Palomar/Zwicky Transient Factories covering large swathes of the sky at regular intervals, searching for eruptive variable sources. Those surveys are conducted primarily at optical wavelengths, but there have been instances of sources that have been most prominent at longer wavelengths. SPIRITS, the Spitzer Infrared Intensive Transient Survey, aims to probe those sources by using the Spitzer IRAC camera to monitor 194 nearby galaxies at 3.6 and 4.5 microns. The Spitzer observaitons started in 2011, and have extended as a legacy program that will span HST Cycle 23. In the initial years, numerous variable stars were detected together with 40 transients were detected, including 21 supernovae and 4 novae. The remaining 15 transients have soemwhat perplexing properties: less luminous than supernovae, but more luminous than novae or AGB stars, generally located in spiral arms and lacking bright optical counterparts. The present program aims to use Hubble to obtain detailed, high angular resolution images of those mir-infrared transients with the goal of determining their nature.

Past weeks:
page by Neill Reid, updated 23/12/2014
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