This week on HST


HST Programs: November 14 - November 20, 2016

Program Number Principal Investigator Program Title
14081 Thierry Lanz, Observatoire de la Cote d'Azur Probing Supernovae Chemical Yields in Low Metallicity Environments with UV Spectroscopy of Magellanic Cloud B-type Stars
14083 Ismael Perez-Fournon, Instituto de Astrofisica de Canarias The nature and environment of the most luminous starburst galaxies at redshift > 5
14096 Dan Coe, Space Telescope Science Institute - ESA RELICS: Reionization Lensing Cluster Survey
14160 John M. O'Meara, Saint Michaels College A 100 million-fold increase in the measured sizes of neutral gas reservoirs in the early Universe
14164 Ata Sarajedini, University of Florida Exploring the nature and synchronicity of early cluster formation in the Local Group
14182 Thomas H. Puzia, Pontificia Universidad Catolica de Chile The Coma Cluster Core Project
14216 Robert P. Kirshner, Harvard University RAISIN2: Tracers of cosmic expansion with SN IA in the IR
14494 Jonathan Charles Tan, University of Florida Peering to the Heart of Massive Star Birth. II. Completion of the Eight-Source Pilot Survey
14497 Renske Smit, Durham Univ. Identifying z>12 galaxies with JWST: What sources produce strong UV emission lines?
14606 Brooke Devlin Simmons, University of California - San Diego Secular Black Hole Growth and Feedback in Merger-Free Galaxies
14618 Michael Shara, American Museum of Natural History Ultraviolet Flashers in M87: Rapidly Recurring Novae as SNIa Progenitors
14644 Pieter van Dokkum, Yale University Exploring the extremely low surface brightness sky: distances to 23 newly discovered objects in Dragonfly fields
14649 Katherine Anne Alatalo, Carnegie Institution of Washington Opening a New Window into Galaxy Evolution Through the Lens of CO-detected Shocked Poststarburst Galaxies
14664 Thomas G. Beatty, The Pennsylvania State University Phase-Resolved Emission Spectroscopy of the Transiting Brown Dwarf KELT-1b Using WFC3
14675 Julia Christine Roman-Duval, Space Telescope Science Institute - ESA Metal Evolution and TrAnsport in the Large Magellanic Cloud (METAL): Probing Dust Evolution in Star Forming Galaxies
14688 Paul Goudfrooij, Space Telescope Science Institute Extended Star Formation or a Range of Stellar Rotation Velocities? The Nature of Extended Main Sequence Turnoffs in Intermediate-Age Star Clusters
14705 Martin A Cordiner, Catholic University of America Confirming interstellar C60+ using a new method for high signal-to-noise NIR STIS spectroscopy
14734 Nitya Kallivayalil, The University of Virginia Milky Way Cosmology: Laying the Foundation for Full 6-D Dynamical Mapping of the Nearby Universe
14752 John T. Clarke, Boston University Variability in the Escape of Water from Mars
14762 Justyn Robert Maund, University of Sheffield A UV census of the sites of core-collapse supernovae
14766 Joshua D. Simon, Carnegie Institution of Washington ACS Imaging of the Ultra-Faint Dwarf Galaxy Reticulum II: Age-Dating a Unique Nucleosynthetic Event
14767 David Kent Sing, University of Exeter The Panchromatic Comparative Exoplanetary Treasury Program
14779 Melissa Lynn Graham, University of Washington A NUV Imaging Survey for Circumstellar Material in Type Ia Supernovae
14840 Andrea Bellini, Space Telescope Science Institute Schedule Gap Pilot
14862 Ariel Goobar, Stockholm University Resolving the multiple images of the strongly lensed SNIa iPTF16geu

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 14182: The Coma Cluster Core Project


Hubble image covering part of the central regions of the Coma cluster
The Coma cluster is the nearest rich galaxy cluster, lying at a distance of ~100 Mpc from the Milky Way. The cluster includes well over 1000 major galaxies, centred on two giant ellipticals, NGC 4874 and NGC 4889. Chandra observations show that the galaxies are embedded in very hot intracluster gas (see this site ). Cluster galaxies have also been surveyed at mid-infrared wavelengths by Spitzer, and in the ultraviolet by GALEX. Individual galaxies have been studied in the past using HST. In Cycle 15 the Advanced Camera for Surveys started a systematic imaging with ACS (with parallel observations with NICMOS) of the cluster core ( a 7x6 mosaic, covering approximately 400 sq. arcmin.), together with 40 fields at larger radii.That program was curtailed by the failure of ACS in January 27th. The present program builds on those observations, using Wide-Field Camera 3 to obtain complementary UV and IR data for the existing ACS images. ACS itself is being used in parallel to cover other regions with the cluster. Those observations will be capable of detecting dwarf galaxies with absolute magnitudes as faint as MB ~ -8, fainter than most of the Milky Way's dwarf spheroidal companions. Besides completing a detailed census of the low luminosity tail of the galaxian mass function, the observations will be used to probe colour gradients and internal chemical evolution.

GO 14216: RAISIN2: Tracers of cosmic expansion with SN IA in the IR


The first supernova discovered by the Pan-STARRs survey
Supernovae are the most spectacular form of stellar obituary. In recent years, these celestial explosions have acquired even more 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 uncertainties remain as to the uniformity of the events. Moreover, as the sample of known supernova has grown, so has the range of photometric systems and the methods used to fit the light curve and account for the ever-present uncertainites inroduced by dust absorption. Consequently, the potential remains for systematic bias in distance estimates due both to intrinsic differences and to measurement errors. The present program builds on a Cycle 21 program, and aims to minimise these systematics by compiling standard sequences of observations, primarily in the Y, J, and H filters, of supernovae at redshifts between z~0.3 and 0.5. Focusing on those wavelengths minises the effects, and hence the uncertainties, due to dust absorption. The supernovae themselves are drawn from the Pan-STARRS survey, with the WFC3-IR camera on HST employed to obtain the photometry.

GO 14734: Milky Way Cosmology: Laying the Foundation for Full 6-D Dynamical Mapping of the Nearby Universe


The low-mass dwarf galaxy, Leo II
The Milky Way, M31 and M33 are the three largest galaxies in the Local Group. That system, however, includes more than 25 other members, with the majority being dwarf spheroidal galaxies that are satellites of either M31 or the Milky Way. Those galaxies have old, evolved stellar populations, and even the most prominent have masses that are less than a few x 107 MSun, or 10-4 that of the Milky Way. All of these galaxies are moving in the potential set by the overall Local Group system, but dominated by M31 and the Milky Way. Determining full space motions for the dwarfs therefore provide a means of constraining that potential. Even though the galaxies, and their brightest stellar constituents, are faint, measuring radial velocity is a relatively straightforward procedure. Deriving tangential motions is not, since the typical proper motions of these systems are a few mas/year at best. The present proposal aims to capitalise on the exceptional resolution and high stability of HST to address this issue. Wide Field Camera 3 and the Advanced Camera for Surveys will be used to obtain first epoch observations of the 32 known dwarf galaxies within 420 kpc. that currently lack such data. These observations will lay the foundation for future observations with both HST and future missions, including JWST and WFIRST.

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