This week on HST


HST Programs: March 28, 2011 - April 3, 2011

Program Number Principal Investigator Program Title
11616 Gregory J. Herczeg, Max-Planck-Institut fur extraterrestrische Physik The Disks, Accretion, and Outflows {DAO} of T Tau stars
11644 Michael E Brown, California Institute of Technology A dynamical-compositional survey of the Kuiper belt: a new window into the formation of the outer solar system
12008 Albert Kong, National Tsing Hua University Primordial formation of close binaries in globular clusters with low density cores
12060 Sandra M. Faber, University of California - Santa Cruz Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey -- GOODS-South Field, Non-SNe-Searched Visits
12063 Sandra M. Faber, University of California - Santa Cruz Galaxy Assembly and the Evolution of Structure over the First Third of Cosmic Time - I
12066 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12069 Marc Postman, Space Telescope Science Institute Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos
12161 David R. Ardila, Jet Propulsion Laboratory Accretion in Close Pre-Main-Sequence Binaries
12169 Boris T. Gaensicke, The University of Warwick The frequency and chemical composition of planetary debris discs around young white dwarfs
12176 Jonathan D. Nichols, University of Leicester Long term observations of Saturn's northern auroras
12180 John M. Cannon, Macalester College The Holistic Evolution of Dwarf Galaxies: Internal and External Processes in NGC 6822
12209 Adam S. Bolton, University of Utah A Strong Lensing Measurement of the Evolution of Mass Structure in Giant Elliptical Galaxies
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
12228 Glenn Schneider, University of Arizona Probing for Exoplanets Hiding in Dusty Debris Disks: Inner {<10 AU} Disk Imaging, Characterization, and Exploration
12248 Jason Tumlinson, Space Telescope Science Institute How Dwarf Galaxies Got That Way: Mapping Multiphase Gaseous Halos and Galactic Winds Below L*
12251 Zachory K. Berta, Harvard University The First Characterization of a Super-Earth Atmosphere
12269 Claudia Scarlata, California Institute of Technology The escape of Lya photons in star-forming galaxies
12278 Thomas R. Ayres, University of Colorado at Boulder Advanced Spectral Library Project: Cool Stars
12289 J. Christopher Howk, University of Notre Dame A COS Snapshot Survey for z < 1.25 Lyman Limit Systems
12292 Tommaso L. Treu, University of California - Santa Barbara SWELLS: doubling the number of disk-dominated edge-on spiral lens galaxies
12296 Howard E. Bond, Space Telescope Science Institute HST Observations of Astrophysically Important Visual Binaries
12310 Goeran Oestlin, Stockholm University LARS - The Lyman Alpha Reference Sample
12311 Giampaolo Piotto, Universita di Padova Multiple Stellar Populations in Galactic Globular Clusters
12314 Daniel Apai, University of Arizona Mapping Brown Dwarfs: The Evolution of Cloud Properties Through the L/T Transition
12320 Brian Chaboyer, Dartmouth College The Ages of Globular Clusters and the Population II Distance Scale
12324 C. S. Kochanek, The Ohio State University The Temperature Profiles of Quasar Accretion Disks
12361 Alexander Brown, University of Colorado at Boulder Chandra X-ray and HST/COS+STIS UV Spectroscopy of Low-Mass Stars in the 9 Myr Old TW Hya Association

Selected highlights

GO 11644: A dynamical-compositional survey of the Kuiper belt: a new window into the formation of the outer solar system

The view from Sedna: an artist's impression The Kuiper Belt lies beyond the orbit of Neptune, extending from ~30 AU to ~50 AU from the Sun, and includes at least 70,000 objects with diameters exceeding 100 km. Setting aside Pluto, the first trans-Neptunian objects were discovered in the early 1990s. Most are relatively modest in size, with diameters of a few hundred km and photometric properties that suggested an icy composition, similar to Pluto and its main satellite, Charon. Over the last three years, a handful of substantially larger bodies have been discovered, with diameters of more than 1000 km; one of the objects, 2003 UB313, is comparable in size to Pluto (2320 km.). At the same time, ground-based surveys, such as the Deep Ecliptic Survey, the Canada-France Ecliptic plane Survey and the Palomar Quest Survey, scanned the ecliptic for fainter, lower-mass objects, with the aim of using their properties to assess the likely chemical composition and dynamical history of the early Solar System. The present program will use Wide Field Camera 3 to push up to 2 magnitudes fainter than these ground-based studies, providing reliable estimates of compositions for a representative sample of KBOs.
GO 12060/12063: Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey

Part of the GOODS/Chandra Deep Field South field, as imaged by HST 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 follow-up.

GO 12176: Long term observations of Saturn's northern aurora

Saturnian aurorae Planetary aurorae are stimulated by the influx of charged particles from the Sun, which travel along magnetic field lines and funnel into the atmosphere near the magnetic poles. Aurorae therefore require that a planet has both a substantial atmosphere and a magnetic field. They are a common phenomenon on Earth, sometimes visible at magnetic latitudes more than 40 degrees from the pole, and have also been seen on Jupiter, Saturn, Uranus and Neptune. In August 2009, Saturn passed through its equinox, with the Sun moving into the northern Saturnian hemisphere, and Earth crossing the ring plane in mid-September. As a result, Saturn's northern pole has now become accessible to direct observations. This proposal aims to use the ACS/SBC to study aurorae in the northern hemisphere, coordinating with observations by the Cassini mission, and allowing comparison of their characteristics against observations of southern aurorae from previous years. In particular, the southern aurorae tend to occur in an oval whose centre is displaced from the south (rotational) pole. Does the northern hemisphere exhibit a similar phenomenon?

GO 12292: SWELLS: doubling the number of disk-dominated edge-on spiral lens galaxies

ACS images of galaxy-galaxy Einstein ring lenses from the Sloan survey Gravitational lensing is a consequence the theory of general relativity. Its importance as an astrophysical tool first became apparent with the realisation (in 1979) that the quasar pair Q0957+561 actually comprised two lensed images of the same background quasar. In the succeeding years, lensing has been used primarily to probe the mass distribution of galaxy clusters, using theoretical models to analyse the arcs and arclets that are produced by strong lensing of background galaxies, and the large-scale mass distribution, through analysis of weak lensing effects on galaxy morphologies. Gravitational lensing can also be used to investigate the mass distribution of individual galaxies; in particular, important questions remain regarding the dark matter profiles of spiral galaxies, and how dark matter responds to and/or reacts to the formation of disk systems. The present program aims to identify edge-on spiral galaxies that are lensing background sources. As edge-on systems, the observed rotation curves give the rotational velocities directly which, combined with the lensing measurements, allows deconvolution of the relative contributions of dark and visible material. present program is using ACS to survey 16 candidate systems, with the expectation that around half will be confirmed as lensing systems.

Past weeks:
page by Neill Reid, updated 2/5/2011