This week on HST


HST Programs: July 4, 2011 - July 10, 2011

Program Number Principal Investigator Program Title
12014 Michael R. Garcia, Smithsonian Institution Astrophysical Observatory Continued M31 Monitoring for Black Hole X-ray Nova
12025 James C. Green, University of Colorado at Boulder COS-GTO: QSO Absorbers, Galaxies and Large-scale Structures in the Local Universe Part 2
12035 James C. Green, University of Colorado at Boulder COS-GTO: Activity of Solar Mass Stars from Cradle to Grave Part 2
12069 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12071 Julianne Dalcanton, University of Washington A Panchromatic Hubble Andromeda Treasury - I
12073 Julianne Dalcanton, University of Washington A Panchromatic Hubble Andromeda Treasury - I
12099 Adam Riess, The Johns Hopkins University Supernova Follow-up for MCT
12169 Boris T. Gaensicke, The University of Warwick The frequency and chemical composition of planetary debris discs around young white dwarfs
12181 Drake Deming, University of Maryland The Atmospheric Structure of Giant Hot Exoplanets
12192 James T. Lauroesch, University of Louisville Research Foundation, Inc. A SNAPSHOT Survey of Interstellar Absorption Lines
12193 Jae-Woo Lee, Sejong University Globular clusters as galaxy building blocks
12210 Adam S. Bolton, University of Utah SLACS for the Masses: Extending Strong Lensing to Lower Masses and Smaller Radii
12212 D. Michael Crenshaw, Georgia State University Research Foundation What are the Locations and Kinematics of Mass Outflows in AGN?
12215 Nancy R. Evans, Smithsonian Institution Astrophysical Observatory Searching for the Missing Low-Mass Companions of Massive Stars
12225 Ansgar Reiners, Georg-August-Universitat Imaging accretion sources and circumbinary disks in young brown dwarfs
12227 Raghvendra Sahai, Jet Propulsion Laboratory Tracking the Evolution of a Knotty, High-Speed Jet in the Carbon Star, V Hydrae
12228 Glenn Schneider, University of Arizona Probing for Exoplanets Hiding in Dusty Debris Disks: Inner {<10 AU} Disk Imaging, Characterization, and Exploration
12237 William M. Grundy, Lowell Observatory Orbits, Masses, Densities, and Colors of Two Transneptunian Binaries
12258 Karl D. Gordon, Space Telescope Science Institute The Environmental Dependence of Ultraviolet Dust Extinction Curves in the Small Magellanic Cloud
12283 Matthew A. Malkan, University of California - Los Angeles WFC3 Infrared Spectroscopic Parallel Survey {WISP}: A Survey of Star Formation Across Cosmic Time
12287 Scott D. Friedman, Space Telescope Science Institute Constraining Models of Deuterium Depletion and Galactic Chemical Evolution with Improved Measurements of D/H
12307 Andrew J. Levan, The University of Warwick A public SNAPSHOT survey of gamma-ray burst host galaxies
12310 Goeran Oestlin, Stockholm University LARS - The Lyman Alpha Reference Sample
12314 Daniel Apai, University of Arizona Mapping Brown Dwarfs: The Evolution of Cloud Properties Through the L/T Transition
12316 John P. Wisniewski, University of Washington HST/FGS Astrometric Search for Young Planets Around Beta Pic and AU Mic
12320 Brian Chaboyer, Dartmouth College The Ages of Globular Clusters and the Population II Distance Scale
12446 Michael Shara, American Museum of Natural History Ionization and Light Echoes in the T Pyxidis Nebula
12448 Arlin Crotts, Columbia University in the City of New York Towards a Detailed Understanding of T Pyx, Its Outbursts and Shell
12680 Julianne Dalcanton, University of Washington Panchromatic Hubble Andromeda Treasury Charge Injection Test

Selected highlights

GO 12099: Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey - SNe follow-up

High redshift supernovae from HST observations in previous cycles CANDELS is one of three Multi-Cycle Treasury Program, whose observations will be executed over the next three HST Cycles. It builds on past investment of both space- and ground-based observational resources. In particular, it includes coverage of the two fields of 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. The CANDELS program is capitalising on this large investment, with new observations with WFC3 and ACS on both GOODS fields, and on three other fields within the COSMOS, EGS and UDS survey areas (see this link for more details). The prime aims of the program are twofold: reconstructing the history of galaxy formation, star formation and nuclear galactic activity at redshifts between z=8 and z=1.5; and searching for high-redshift supernovae to measure their properties at redshifts between z~1 and z~2. The program incorporates a tiered set of observations that complement, in areal coverage and depth, the deep UDF observations, while the timing of individual observations will be set to permit detection of high redshift SNe candidates, for subsequent separate follow-up. The present observations target a high-redshift supernova identified in the course of the survey imaging.

GO 12237: Orbits, Masses, and Densities of Two Transneptunian Binaries

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 Kuiper Belt consists of icy planetoids that orbit the Sun within a broad band stretching from Neptune's orbit (~30 AU) to distance sof ~50 AU from the Sun (see David Jewitt's Kuiper Belt page for details). 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. Approximately 2% of the known KBOs are binary (including Pluto, one of the largest known KBOs, regardless of whether one considers it a planet or not). This is a surprisingly high fraction, given the difficulties involved in forming such systems and the relative ease with which they can be disrupted. It remains unclear whether these systems formed from single KBOs (through collisions or 3-body interactions) as the Kuiper Belt and the Solar System have evolved, or whether they represent the final tail of an initial (much larger) population of primordial binaries. These issues can be addressed, at least in part, through deriving a better understanding of the composition of KBOs - and those properties can be deduced by measuring the orbital parameters for binary systems. The present proposal aims to use the WFC3/UVIS camera to determine the relative orbits for two known KBO binaries, selecting targets that are also being observed at mid-IR wavelengths by herschel. Just as with binary stars, the orbital period and semi-major axis give the total system mass, while the mid-infrared properties (measured by Spitzer) allow an assessment of the surface area/diameters; combining these measurements gives an estimate of the mean density.

GO 12316: HST/FGS Astrometric Search for Young Planets Around Beta Pic and AU Mic

The extended disk around the M dwarf, AU Mic Planet formation occurs in circumstellar disks around young stars. Most of the gaseous content of those disks dissipates in less than 10 million years, leaving dusty debris disks that are detectable through reflect light at near-infrared and, to a lesser extent, optical wavelengths. The disk structure is affected by massive bodies (i.e. planets and asteroids), which, through dynamical interactions and resonances, can produce rings and asymmetries. Two of the most prominent and best characterised disks are those acompanying the A-type star Beta Pictoris, and the nearby (d~10 parsec) early-type M dwarf, AU Mic. Both stars are young, with age estimates ranging from 8 to 20 million years for beta Pic and 5 to 10 million years for AU Mic. beta Pic's disk, in particular, shows evidence for significant sub-structure that has been attributed to planetary companions. The present HST program aims to use the Fine Guidance Sensors to obtain high precision astrometry of these two young stars, and search for systematic astrometric residuals due to the hypothesised planetary companions. Upcoming observations focus primarily on AU Mic.

GO 12446: Ionization and Light Echoes in the T Pyxidis Nebula

Artist's impression of the recurrent nova, RS Oph (by David Hardy) Recurrent novae are generally agreed to be close binary systems, comprising a white dwarf and a companion main sequence star that is overflowing its Roche lobe, leading to period transfers of mass onto the white dwarf surface. The mass transfer episode triggers nuclear ractions, which lead the star increasing significantly in it luminosity. T Pyxidis is one such system, and it exhibited fairly regular outbursts every 20 years between its discovery, in 1890, and 1966. Since then, however, it has been dormant, a prolonged period of quiescence that led to suggestions, earlier this year, that it might either be headed for hibernation, or in the process of accumulating sufficient mass to trigger a type Ia supernova explosion (in about 1 million years). Perhaps prompted by these suggestions (a la Monty Python Mary Queen of Scots radio sketch), T Pyxidis erupted into activity on or around April 15th. A first set of observation with HST, designed to obtain H-alpha images of the illuminated ejecta, were obtained on April 18th, with subsequent images taken on April 30th and a third set on July 8th. Additional observations will be taken later this year and early next year, with the aim of tracing the development of any light echoes.
Past weeks:
page by Neill Reid, updated 2/5/2011