This week on HST


HST Programs: August 8 - August 14, 2016

Program Number Principal Investigator Program Title
13760 Derck L. Massa, Space Science Institute Filling the gap --near UV, optical and near IR extinction
14069 Nate Bastian, Liverpool John Moores University Searching For Multiple Populations in Massive Young and Intermediate Age Clusters
14074 Roger Cohen, Universidad de Concepcion Opening the Window on Galaxy Assembly: Ages and Structural Parameters of Globular Clusters Towards the Galactic Bulge
14096 Dan Coe, Space Telescope Science Institute - ESA RELICS: Reionization Lensing Cluster Survey
14098 Harald Ebeling, University of Hawaii Beyond MACS: A Snapshot Survey of the Most Massive Clusters of Galaxies at z>0.5
14120 Jarle Brinchmann, Universiteit Leiden He II emission as a tracer of ultra-low metallicity and massive star evolution
14127 Michele Fumagalli, Durham Univ. First Measurement of the Small Scale Structure of Circumgalactic Gas via Grism Spectra of Close Quasar Pairs
14128 Mark Hollands, The University of Warwick The dawn of rocky planet formation
14141 Guy Worthey, Washington State University NGSL Extension 1. Hot Stars and Evolved Stars
14178 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey: The WISP Deep Fields
14181 S Thomas Megeath, University of Toledo A Snapshot WFC3 IR Survey of Spitzer/Hershel-Identified Protostars in Nearby Molecular Clouds
14209 Brian Siana, University of California - Riverside The Final UV Frontier: Legacy Near-UV Imaging of the Frontier Fields
14212 Karl Stapelfeldt, Jet Propulsion Laboratory A Snapshot Imaging Survey of Spitzer-selected Young Stellar Objects in Nearby Star Formation Regions*.t23
14227 Casey Papovich, Texas A & M University The CANDELS Lyman-alpha Emission At Reionization (CLEAR) Experiment
14228 John Charles Raymond, Smithsonian Institution Astrophysical Observatory Thermal Equilibration and Cosmic-Ray Acceleration in Astrophysical Shocks: UV Spectra of the SN1006 Remnant
14235 Sangmo Tony Sohn, Space Telescope Science Institute Globular Cluster Orbits from HST Proper Motions: Constraining the Formation and Mass of the Milky Way Halo
14249 Roberto Mignani, INAF, Istituto di Astrofisica Spaziale e Fisica The old pulsar PSR J0108-1431, a key target to understand the long-term evolution of neutron stars
14264 Glenn G. Kacprzak, Swinburne University of Technology A New Dual Perspective of Mutli-phase Galaxy Outflows
14268 Nicolas Lehner, University of Notre Dame Project AMIGA: Mapping the Circumgalactic Medium of Andromeda
14277 John Thomas Stocke, University of Colorado at Boulder Probing Hot Gas in Spiral-Rich Galaxy Groups
14346 Chris S. Kochanek, The Ohio State University Constraining the Position of the Most Luminous Supernova Ever Foundb
14362 Lucas Johnson, University of Alabama Searching for Fossil Group Progenitors Via Strong Gravitational Lensing
14364 Roger Romani, Stanford University PSR J2124-3358: A Unique, Isolated MSP/PWN/Bowshock
14494 Jonathan Charles Tan, University of Florida Peering to the Heart of Massive Star Birth. II. Completion of the Eight-Source Pilot Survey
14648 Adam Riess, The Johns Hopkins University A New Threshold of Precision, 30 micro-arcsecond Parallaxes and Beyond
14814 Shriharsh Tendulkar, McGill University Searching the IR counterpart of the mysterious central object in RCW 103

Selected highlights

GO 14096: RELICS: Reionization Lensing Cluster Survey


Hubble image and mass map for the cluster ACT-CL J0102-4915, one of the clusters included in the RELICS program
The overwhelming majority of galaxies in the universe are found in clusters. As such, those 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, and the Frontier Fields program, targeting six clusters for deep multi-colour imaging. RELICS is focused on using massive galaxy clusters as gravitational telescopes, searching for strongly lensed background galaxies drawn from the high redshift universe. Imaging 46 fields in 41 galaxy clusters, this program aims to identify galaxies with redshifts in the range 9 < z < 12. By targeting strongly-lensing clusters, standard models for galaxy evolution suggest that the program can deliver ~100 galaxies in that redshift range, together with more than 150 galaxies at z~8. A significant number of these galaxies should be brighter than H~25.5, and therefore accessible to more detailed follow-up observations. Conversely, the actual number of galaxies detected will set constraints on the galaxy number-redshift distribution, and the overall formation and assembly history.

GO 14128: The dwan of rocky planet formation


Artist's impression of a comet spiralling in to the white dwarf variable, G29-38
White dwarfs represent the end point for the evolution of low- and intermediate mass stars. As those stars evolve through the red giant phase, the innermost regions of any planetary system will be dwallowed up by the parent star, although mass loss will lead to some orbital expansion. The final white dwarf system may well retain residual material from that epoch, and that material reveals itself through excess flux at near- and mid-infrared wavelengths. In the late 1980s, Ben Zuckerman and Eric Becklin detected just this kind of excess around G29-38, a relatively hot DA white dwarf that also happens to lie on the WD instability strip.Given the orbital lifetimes, those dust particles must be regularly replenished, presumably from rocky remnants of a solar system. G 29-38 stood as a lone prototype for almost 2 decades, until a handful of other dusty white dwarfs were identified from Spitzer observations within the last couple of years.In subsequent years, a significant number of DA white dwarfs have been found to exhibit narrow metallic absorption lines in their spectra. Those lines are generally attributed to "pollution" of the white dwarf atmospheres. Given that the diffusion time for metals within the atmospheres is short (tens to hundreds of years), the only reasonable means of maintaining such lines in ~20% of the DA population is to envisage continuous accretion from a surrounding debris disk. The Cosmic Origins Spectrograph (COS) is an ideal instrument for probing the abundance of trace elements in white dwarfs atmospheres: more than 70 systems have been observed, with detection rates running at around 50%. The present program is using COS to obtain near-UV observations of 3 white dwarfs identified from the SDSS catalogues. All three are known from optical spectra to have substantial metal pollution in the atmospheres. COS spectra will probe metallic lines at UV wavelengths.

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 14227: The CANDELS Lyman-alpha Emission At Reionization (CLEAR) Experiment


Part of the GOODS/Chandra Deep Field South field, as imaged by HST
Hubble has made significant contributions in many science areas, but galaxy formation, assembly and evolution is a topic that has been transformed by the series of deep fields obtained over the past 20 years. CANDELS, one of three Multi-Cycle Treasury Program executed in cycles 18 through 20, is one of the more recent additions to this genre.Building on past investment of both space- and ground-based observational resources, it covers five five fields including both the Great Observatory Origins Deep Survey (GOODS), centred on the northern Hubble Deep Field (HDF) in Ursa Major and the Chandra Deep Field-South in Fornax. In addition to deep HST data at optical and near-infrared wavelengths, the fields have been covered at X-ray wavelengths by Chandra (obviously) and XMM-Newton; at mid-infrared wavelengths with Spitzer; and ground-based imaging and spectroscopy using numerous telescopes, including the Kecks, Surbaru and the ESO VLT. This represents an accumulation of almost 1,000 orbits of HST time, and comparable scale allocations on Chandra, Spitzer and ground-based facilities. CANDELS added new optical and near-infrared observations with WFC3 and ACS (see this link for more details). Those data have been processed and analysed by both the CANDELS team and by other groups within the community. The present program builds on this foundation by adding 16 pointings within the CANDELS fields with the WFC3 G102 grism. The goal is to probe reionisation by measuring the strength of Lyman-alpha absorption in galaxies at redshifts between z=6.5 and z=8.2. The expectation is that the ovall absorption strength should decrease with decreasing redshift as the intergalactic medium is ionised, and the proportion of neutral gas decreases.

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