This week on HST


HST Programs: May 11 - May 17, 2015

Program Number Principal Investigator Program Title
13026 Andrew J. Levan, The University of Warwick XMM-Newton Target of Opportunity of Tidal Disruption Events
13504 Jennifer Lotz, Space Telescope Science Institute HST Frontier Fields - Observations of MACSJ1149.5+2223
13647 Ryan Foley, University of Illinois at Urbana - Champaign Testing the Standardizability of Type Ia Supernovae with the Cepheid Distance of a Twin Supernova
13652 Boris T. Gaensicke, The University of Warwick The frequency and chemical composition of rocky planetary debris around young white dwarfs: Plugging the last gaps
13655 Matthew Hayes, Stockholm University How Lyman alpha bites/beats the dust
13656 Matthew Hayes, Stockholm University Unveiling the Dark Baryons: The First Imaging of Circumgalactic OVI in Emission
13659 Karin Sandstrom, University of California - San Diego A New View of Dust at Low Metallicity: The First Maps of SMC Extinction Curves
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
13690 Tanio Diaz-Santos, Universidad Diego Portales Tracking the Obscured Star Formation Along the Complete Evolutionary Merger Sequence of LIRGs
13692 William M. Grundy, Lowell Observatory Orbits and Physical Properties of Four Binary Transneptunian Objects
13695 Benne W. Holwerda, Sterrewacht Leiden STarlight Absorption Reduction through a Survey of Multiple Occulting Galaxies (STARSMOG)
13711 Abhijit Saha, National Optical Astronomy Observatory, AURA Establishing a Network of Next Generation SED standards with DA White Dwarfs
13728 Steven Kraemer, Catholic University of America Do QSO2s have Narrow Line Region Outflows? Implications for quasar-mode feedback
13731 Eileen T Meyer, Space Telescope Science Institute The Real Impact of Extragalactic Jets on Their Environments: Measuring the Advance Speed of Hotspots with HST
13733 Celine Peroux, Laboratoire d'Astrophysique de Marseille The Stellar Continuum Light from Damped Lyman-alpha Absorber Galaxies Detected with Integral Field Spectroscopy
13740 Daniel Stern, Jet Propulsion Laboratory Clusters Around Radio-Loud AGN: Spectroscopy of Infrared-Selected Galaxy Clusters at z>1.4
13741 Thaisa Storchi-Bergmann, Universidade Federal do Rio Grande do Sul Constraining the structure of the Narrow-Line Region of nearby QSO2s
13750 John M. Cannon, Macalester College Fundamental Parameters of the SHIELD II Galaxies
13756 Saurabh W. Jha, Rutgers the State University of New Jersey Rings within Rings: High Resolution Imaging of a Spectacular Gravitational Lens
13767 Michele Trenti, University of Melbourne Bright Galaxies at Hubble's Detection Frontier: The redshift z~9-10 BoRG pure-parallel survey
13774 Sara Ellison, University of Victoria Feeding and feeback: The impact of AGN on the circumgalactic medium.
13776 Michael D. Gregg, University of California - Davis Completing The Next Generation Spectral Library
13777 Michael D. Gregg, University of California - Davis Morphological Transformation in the Coma Cluster
13787 Nathan Smith, University of Arizona Massive stars dying alone: Extremely remote environments of SN2009ip and SN2010jp
13788 Aida H. Wofford, CNRS, Institut d'Astrophysique de Paris COS Views of Local Galaxies Approaching Primeval Conditions
13793 Rebecca A A Bowler, Royal Observatory Edinburgh Unveiling the merger fraction, sizes and morphologies of the brightest z ~ 7 galaxies
13804 Kristen McQuinn, University of Minnesota - Twin Cities Important Nearby Galaxies without Accurate Distances
13806 Hugues Sana, Space Telescope Science Institute - ESA UV spectroscopy of the most massive overcontact binary known to date: on the verge of coalescence ?
13828 Steve Shore, Universita di Pisa Late nebular stage high resolution UV spectroscopy of classical Galactic novae: a benchmark panchromatic archive for nova evolution
13841 Alexandre Gallenne, Universidad de Concepcion Accurate masses and distances of the binary Cepheids S Mus and SU Cyg
13868 Dale D. Kocevski, Colby College Are Compton-Thick AGN the Missing Link Between Mergers and Black Hole Growth?
13873 Darin Ragozzine, Florida Institute of Technology The Intriguing Formation of Haumea's Satellites
14049 C. S. Kochanek, The Ohio State University Dust to Dust: Monitoring the Evolution of the New Class of Self-Obscured Transient

Selected highlights

GO 13652: The frequency and chemical composition of rocky planetary debris around young white dwarfs: Plugging the last gaps


Artist's impression of a comet spiralling in to the white dwarf variable, G29-38
During the 1980s, one of the techniques used to search for brown dwarfs was to obtain near-infrared photometry of white dwarf stars. Pioneered by Ron Probst (KPNO), the idea rests on the fact that while white dwarfs are hot (5,000 to 15,000K for the typcail targets0, they are also small (Earth-sized), so they have low luminosities; consequently, a low-mass companion should be detected as excess flux at near- and mid-infrared wavelengths. In 1988, 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. However, follow-up observations showed that the excess peaked at longer wavelengths than would be expected for a white dwarf; rather, G 29-38 is surrounded by a dusty disk. 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 presentSNAPSHOT program aims to cap pervious investigations by targeting white dwarfs with cooling ages of 5-25 Myrs and 100-300 Myrs: models suggest that planetary collisions should be frequent at the younger ages, when the parent stars have just completed extensive mass loss on the AGB.

GO 13731: The Real Impact of Extragalactic Jets on Their Environments: Measuring the Advance Speed of Hotspots with HST


A WFPC2 image of the jet in M87
Highly collimated jets are common features of active galactic nuceli and quasars, generally believed to be generated by accretion onto supermassive black holes at the centres of these galaxies. The most famous example is the central jet in the giant elliptical M87, the second brightest galaxy in the Virgo cluster. M87 is a strong radio source, originally detected as Virgo A in 1947. The jet itself was first seen as long ago as 1918, when the lick astronomer Heber Curtis commented on a strange linear feature, a "curious straight ray", in the central regions of the galaxy. Hubble has been observing M87 for more than 20 years, and the high spatial resolution offered by those observations has allowed astronomers to measure the relative motions of features in the jet, The present observations build on that past history for both M87A and the radio galaxy Pictor A. The Advanced Camera for Surveys will be used to obtain moderately deep images of both galaxies, probing the motions of the extreme regions of the jet, the terminal hot spots where the relativistic material in the jet impacts the intergalactic medium.

GO 13767: Bright Galaxies at Hubble's Detection Frontier: The redshift z~9-10 BoRG pure-parallel survey


The ACS optical/far-red image of the Hubble Ultra Deep Field
Galaxy evolution in the early Universe is a discipline of astronomy that has been transformed by observations with the Hubble Space Telescope. The original Hubble Deep Field, the product of 10 days observation in December 1995 of a single pointing of Wide Field Planetary Camera 2, demonstrated conclusively that galaxy formation was a far from passive process. The images revealed numerous blue disturbed and irregular systems, characteristic of star formation in galaxy collisions and mergers. Building on this initial progam, the Hubble Deep Field South (HDFS) provided matching data for a second southern field, allowing a first assessment of likely effects due to field to field cosmic variance, and the Hubble Ultra-Deep Field (UDF) probed to even fainter magitude with the Advanced Camera for Surveys (ACS). The highest redshift objects found in the UDF have redshifts approaching z~7. Pushing to larger distances, and greater ages, demands observatons at near-infrared wavelengths, as the characteristics signatures of star formation are driven further redward in the spectrum. Wide Field Camera 3, installed in Servicing Mission 4, is well suited to these observations, and a number of programs are in place in Cycle 17 that address these issues. Indeed, WFC3 is employed in pure parallel mode by several programs. These take advantage of other science programs, usually with COS, that involve 2-5 orbit pointings on sources at high galactic latitude. The WFC3 pointing is unplanned, since it depends on the orientation adopted for the prime observations, but 2-5 orbits of IR imaging can reach galaxies at redshifts exceeding z=7 (potentially even z~8) in high latitude fields. The present program builds on similar programs in Cycles 17 and 19, and aims to detect the brightest galaxies at z~9, within 600 Myrs of the Big Bang.

GO 13841: Accurate masses and distances of the binary Cepheids S Mus and SU Cyg


The radial velocity curve (left) and pulsational velocity curve (middle) of the primary component of the binary Cepheid, V1334 Cyg (Gallene et al, A&A, 552, A21)
SU Cygni and S Muscae are short-period (P = 3.8 days, 9.66 days) classical Cepheid variables lying at a distance of a few hundred parsecs from the Sun. Both are known binary systems, with SU Cyg harbouring a ~4 solar mass, B6 companion and S Muscae matched with a 3-5 solar mass, B3-B5 companion. At optical wavelengths, the combined flux is dominated by the cooler Cepheid in these systems, but hot companion is detectable at ultraviolet wavelengths. The present program aims to use STIS to obtain ultraviolet spectra that will enable measurement of the radial velocity curve for the hot companions in these systems. Those observations will be combined with existing ground-based measurements of the Cepheid radial velocities, therefore determing velocity curves for both stars. Combining those data with high-precision astrometric measurements from ground-based interferometry will allow a direct measurement of mass and distance for both systems.

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