This week on HST


HST Programs: December 17 - December 23, 2007


Program Number Principal Investigator Program Title Links
10787 Jane Charlton, The Pennsylvania State University Modes of Star Formation and Nuclear Activity in an Early Universe Laboratory Abstract
10907 Scott F. Anderson, University of Washington New Sightlines for the Study of Intergalactic Helium: A Dozen High-Confidence, UV-Bright Quasars from SDSS/GALEX Abstract
10915 Julianne Dalcanton, University of Washington ACS Nearby Galaxy Survey Abstract
10928 John Subasavage, Georgia State University Research Foundation Calibrating Cosmological Chronometers: White Dwarf Masses Abstract
11079 Luciana Bianchi, The Johns Hopkins University Treasury Imaging of Star Forming Regions in the Local Group: Complementing the GALEX and NOAO Surveys Abstract
11080 Daniela Calzetti, University of Massachusetts Exploring the Scaling Laws of Star Formation Abstract
11083 Patrick Cote, Dominion Astrophysical Observatory The Structure, Formation and Evolution of Galactic Cores and Nuclei Abstract
11107 Timothy M. Heckman, The Johns Hopkins University Imaging of Local Lyman Break Galaxy Analogs: New Clues to Galaxy Formation in the Early Universe Abstract
11113 Keith S. Noll, Space Telescope Science Institute Binaries in the Kuiper Belt: Probes of Solar System Formation and Evolution Abstract
11128 David Bradley Fisher, University of Texas at Austin Time Scales Of Bulge Formation In Nearby Galaxies Abstract
11142 Lin Yan, California Institute of Technology Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3 Abstract
11144 Richard Bouwens, University of California, Santa Cruz Building on the Significant NICMOS Investment in GOODS: A Bright, Wide-Area Search for z>=7 Galaxies Abstract
11145 Nuria Calvet, University of Michigan Probing the Planet Forming Region of T Tauri Stars in Chamaeleon Abstract
11155 Marshall D. Perrin, University of California - Berkeley Dust Grain Evolution in Herbig Ae Stars: NICMOS Coronagraphic Imaging and Polarimetry Abstract
11165 Joshua Winn, Massachusetts Institute of Technology The Radius of the Super-Neptune HD 149026b Abstract
11169 Michael E. Brown, California Institute of Technology Collisions in the Kuiper belt Abstract
11175 Sandra M. Faber, University of California - Santa Cruz UV Imaging to Determine the Location of Residual Star Formation in Galaxies Recently Arrived on the Red Sequence Abstract
11176 Andrew S. Fruchter, Space Telescope Science Institute Location and the Origin of Short Gamma-Ray Bursts Abstract
11178 William M. Grundy, Lowell Observatory Probing Solar System History with Orbits, Masses, and Colors of Transneptunian Binaries Abstract
11187 Mark Showalter, SETI Institute A Deep Search for Martian Dust Rings Abstract
11199 Lee W. Hartmann, University of Michigan A Hard Look at Stellar Disks at the Epoch of Planet Formation Abstract
11202 Leon Koopmans, Kapteyn Astronomical Institute The Structure of Early-type Galaxies: 0.1-100 Effective Radii Abstract
11211 George Fritz Benedict, University of Texas at Austin An Astrometric Calibration of Population II Distance Indicators Abstract
11219 Alessandro Capetti, Osservatorio Astronomico di Torino Active Galactic Nuclei in nearby galaxies: a new view of the origin of the radio-loud radio-quiet dichotomy? Abstract
11220 Jeff Cooke, University of California - Irvine Direct Detection and Mapping of Star Forming Regions in Nearby, Luminous Quasars Abstract
11222 Michael Eracleous, The Pennsylvania State University Direct Detection and Mapping of Star Forming Regions in Nearby, Luminous Quasars Abstract
11225 C. S. Kochanek, The Ohio State University Research Foundation The Wavelength Dependence of Accretion Disk Structure Abstract
11344 Alan Marscher, Boston University Velocity Gradients in the Jets of BL Lac Objects Abstract
11361 Keith Noll, Space Telescope Science Institute Hubble Heritage Observations of Mars at 2007 Opposition Abstract

Some selected highlights

GO 11079: Treasury Imaging of Star Forming Regions in the Local Group: Complementing the GALEX and NOAO Surveys \

The star forming region, N11, in the Small Magellanic Cloud Star formation is a complex process that takes place on many scales, from diffuse, low-level activity within dispersed clouds like the nearby Taurus association, through massive star forming regions, like Orion and 30 Doradus, to intense starbursts within galactic nucle and mergers. The aim of the present proposal is to use WFPC2 to survey a representative sample of active star-forming regions in local Group galaxies. In particular, the observations will cover a wide range of OB associations in the two nearest large spirals, the Andromeda galaxy, M31, and the Triangulum system, M33. Multicolour, high-resolution images, taken at passbands from the ultraviolet (F170W) to far-red (F814W) will allow H-R diagrams to be constructed, probing the distribution of ages and metallicities, and setting constraints on variations in the underlying initial mass function(s). In the coming week, observations are scheduled of OB associations in the M33.

GO 11113: Binaries in the Kuiper Belt: Probes of Solar System Formation and Evolution

A composite of HST images of the Kuiper Belt binary, WW31 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 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. This proposal will use WFPC2 imaging of known KBOs to identify new binary systems.

GO 11142: Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3

NICMOS image of the nearby luminous IR galaxy, Arp 299 Luminous infrared galaxies (LIRGs) have total luminosities that exceed 1011.4 LSun, with most of the energy emitted at wavelengths longward of 10 microns. Many (perhaps most) of these galaxies are interacting or merging disk galaxies, with the excess infrared luminosity generated by warm dust associated with the extensive star formation regions. Many systems also exhibit an active nucleus, and may be in the process of evolving towards an S0 or elliptical merger remnant. The present program is targeting systems with redshifts in the range 0.3 < z < 2.7, combining imaging at near-infrared (NICMOS on HST) and mid-infrared (MIPS on Spitzer) wavelengths. All of the systems already have Spitzer mid-infrared spectra, allowing not only an accurate characterisation of the over all flux distribution, and a \ determination of the total luminosity, but also providing insight into the galaxian dust content and chemical evolution.

GO 11361: Hubble Heritage Observations of Mars at 2007 Opposition

HST images of Mars oppositions over the last decade Mars lies at an average distance of 228 million kilometres, or 1.52 AU, from the Sun, and has an orbital period of 687 days. As a result, it comes into opposition with Earth (i.e. the Sun, Earth and Mars lie along a str\ aight line) once every 780 days, or approximately every 2 years. At that time, Mars makes its closest approach, but the actual distance varies significantly from opposition to opposition since the Martian orbit has significant eccentricity (e=0.093, as compared with e=0.007 for Earth). HST has been systematically observing Mars at opposition since February 1995, 15 months after WFPC2 was installed in Servicing Mission 1. At that time, the planet lay at a distance of 101 million kilometres from Earth and subtended a diameter less than 14 arcseconds. Succeeding oppositions were at increasingly smaller separations, until the opposition of August 28 2003, when Mars was only 55.8 million miles away with an angular diameter of 25.1 arcseconds, its closest approach since 57,617 BCE (but we won't have to wait quite so long - Mars passes even closer on August 28 2287). As in past years, HST will take a series of images of Mars as it approaches opposition, which, this year, will be at 19:47 UT (2:47 pm EST) on Christmas Eve. At that time, Mars will lie at a distance of 88.2 million kilometres with a diameter of 15.2 arcseconds.

Past weeks:
page by Neill Reid, updated 19/12/2007