This week on HST

HST Programs: August 18 - August 24, 2008

Program Number Principal Investigator Program Title Links
10872 Harry Teplitz, California Institute of Technology Lyman Continuum Emission in Galaxies at z=1.2 Abstract
11072 Carole A. Haswell, Open University Measuring the Physical Properties of the first two WASP transiting extrasolar planets Abstract
11101 Gabriela Canalizo, University of California - Riverside The Relevance of Mergers for Fueling AGNs: Answers from QSO Host Galaxies Abstract
11113 Keith S. Noll, Space Telescope Science Institute Binaries in the Kuiper Belt: Probes of Solar System Formation and Evolution Abstract
11130 Luis Ho, Carnegie Institution of Washington AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge Paradigm, Part II Abstract
11136 Michael C. Liu, University of Hawaii Resolving Ultracool Astrophysics with Brown Dwarf Binaries Abstract
11156 Kathy Rages, SETI Institute Monitoring Active Atmospheres on Uranus and Neptune Abstract
11157 Joseph H. Rhee, University of California - Los Angeles NICMOS Imaging Survey of Dusty Debris Around Nearby Stars Across the Stellar Mass Spectrum Abstract
11172 Arlin Crotts, Columbia University in the City of New York Defining Classes of Long Period Variable Stars in M31 Abstract
11178 William M. Grundy, Lowell Observatory Probing Solar System History with Orbits, Masses, and Colors of Transneptunian Binaries Abstract
11192 Hao-Jing Yan, Observatories of the Carnegie Institution of Washington NICMOS Confirmation of Candidates of the Most Luminous Galaxies at z > 7 Abstract
11203 Kevin Luhman, The Pennsylvania State University A Search for Circumstellar Disks and Planetary-Mass Companions around Brown Dwarfs in Taurus Abstract
11205 James Muzerolle , university of Arizona The Effects of Multiplicity on the Evolution of Young Stellar Objects: A NICMOS Imaging Study Abstract
11211 George Fritz Benedict, University of Texas at Austin An Astrometric Calibration of Population II Distance Indicators Abstract
11218 Howard E. Bond, Space Telescope Science Institute Snapshot Survey for Planetary Nebulae in Globular Clusters of the Local Group Abstract
11221 Julianne Dalcanton, University of Washington A Dark Core in Abell 520 Abstract
11235 Jason A. Surace, California Institute of Technology HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies in the Local Universe Abstract
11237 Lutz Wisotzki, Astrophysikalisches Institut Potsdam The origin of the break in the AGN luminosity function Abstract
11512 Mark Raboin Swain, Jet Propulsion Laboratory Molecules in Exoplanet Atmospheres Abstract
11544 Adam L. Kraus, California Institute of Technology The Dynamical Legacy of Star Formation Abstract
11545 Ben Davies, Rochester Institute of Technology A NICMOS survey of newly-discovered young massive clusters Abstract
11548 S. Thomas Megeath, University of Toledo NICMOS Imaging of Protostars in the Orion A Cloud: The Role of Environment in Star Formation Abstract

Some selected highlights

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 11157: NICMOS Imaging Survey of Dusty Debris Around Nearby Stars Across the Stellar Mass Spectrum

The debris disk around beta Pic 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 structure of those disks is affected by massive bodies (i.e. planets and asteroids), which, through dynamical interactions and resonances, can produce rings and asymmetries. Analysis of the rangle of morphological structure in these systems provides insight into the distribution of properties of planetary systems. HST currently provides the only means of achieving the high-contrast required for the detection of these scattered light disks in the presence of the bright parent stars. The present proposal is using NICMOS to target 22 nearby stars that have a strong mid-infrared excess, based on combining optical, near-infrared and mid-infrared IRAS observations. Most of the targets are early-type stars, with spectral types ranging from late-B to mid-G.

GO 11192: NICMOS Confirmation of Candidates of the Most Luminous Galaxies at z > 7 231

The history of the Universe in a nutshell.. Current cosmological models predict that the first galaxies started to form very early in the history of the Universe, at redshifts z > 8. Identifying individual galaxies at high redshifts clearly offers one means of probing the details of that formation process. Several recent analyses have succeeded in finding several galaxies at redshifts in the range 6 < z < 7. Those galaxies have relatively high luminosities and corresponding high masses, exceeding 1010 MSun. This suggests that these are relatively mature systems, whose progenitors should be readily detectable at redshifts z > 7. However, deep pencil-beam surveys that reach those limits have faield to find any plausible "dropout" candidates. The present program aims to probe this issue by using NICMOS to target a number of z > 7 candidates from the GOODS wide-field IR survey. The NIC3 F110W and F160W observations can both confirm whether these really are high redshift galaxies, and probe the detailed structure of any such systems.

GO 11544: The Dynamical Legacy of Star Formation

The central regions of the young star cluster, IC 348 General indications are that the overwhleming majority of stars in the Galactic disk form within clusters. Understanding the cluster environment is therefore important to understanding how most stars - and any associated planetary systems - form and evolve. Star-star interactions can lead to truncation of nascent disks, disruption of binary systems and even ejection from the cluster. The present program aims to investigate these issues by surveying the young star cluster, IC 348, with WFPC2, and combining the present set of observations with data from past cycles. Accurate relative astrometry will enable measurement of the relative stellar motions, and hence the cluster velocity dispersion, as well as premitting the identification of any stars with unusually high motions. In addition, these new WFPC2 images will push observations to fainter limits, potentially revealing new substellar-mass cluster members.

Past weeks:
page by Neill Reid, updated 18/5/2008