This week on HST

HST Programs: August 25 - August 31, 2008

Program Number Principal Investigator Program Title Links
11113 Keith S. Noll, Space Telescope Science Institute Binaries in the Kuiper Belt: Probes of Solar System Formation and Evolution Abstract
11119 Schuyler D. Van Dyk, Jet Propulsion Laboratory The Stellar Origins of Supernovae Abstract
11130 Luis Ho, Carnegie Institution of Washington AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge Paradigm, Part II Abstract
11134 Karen Knierman, University of Arizona WFPC2 Tidal Tail Survey: Probing Star Cluster Formation on the Edge Abstract
11150 James R. Graham, University of California - Berkeley Beta Pic Polarimetry with NICMOS Abstract
11156 Kathy Rages, SETI Institute Monitoring Active Atmospheres on Uranus and Neptune Abstract
11158 R. Michael Rich, University of California - Los Angeles HST Imaging of UV emission in Quiescent Early-type Galaxies Abstract
11167 Sahar S. Allam, Fermi National Accelerator Laboratory A Unique High Resolution Window to Two Strongly Lensed Lyman Break Galaxie 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
11196 Aaron S. Evans, State University of New York at Stony Brook An Ultraviolet Survey of Luminous Infrared Galaxies in the Local Universe Abstract
11205 James Muzerolle , university of Arizona The Effects of Multiplicity on the Evolution of Young Stellar Objects: A NICMOS Imaging Study Abstract
11210 George Fritz Benedict, University of Texas at Austin The Architecture of Exoplanetary Systems 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
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 11134: WFPC2 Tidal Tail Survey: Probing Star Cluster Formation on the Edge

ACS image of the spectacular tidal tail of the Tadpole galaxy, Arp 188 Gravitational interactions between close galaxy pairs produce tidal tails, which can often be sites of extensive star formation in young, gas-rich spiral systems. Within the Milky Way, we know that most stars are born in fairly dense clusters, comparable with the Orion Nebula Cluster, and observatios of nearby sprials (M31, M33) suggest that the same situation pervades in those systems. However, observations suggest that star clusters tend to be rare in tidal tails. The present program is using WFPC2 to obtain R (F606W) and I (F814W) band observations of 12 tidal tail systems, with the aim of quantifying the contribution made by star clusters to star formation in these sparse environments.

GO 11156: Monitoring Active Atmospheres on Uranus and Neptune

Voyager 2 image of Neptune Uranus and Neptune are the two "ice giants" of the Solar System, lying at average distances of 19 and 30 AU from the Sun. At those distances, their atmospheres are subject to much lower solar irradiance than Jupiter or Saturn and, as a result, they tend to show fewer large-scale disturbances. Even so, Neptune showed modest activity in the southern hemisphere between 2000 and 2003, although the disturbances have been less prominent in recent years. Uranus is unique among the major bodies in that it rotates on its side. With a polar obliquity is 98o degrees, its equator is close to perpendicular to the ecliptic plane. Consequently, as it circles the Sun, each pole spends almost half of a Uranian "year" (or 42 terrestrial years) hidden from the Sun in total darkness.On December 7th of this year, Uranus will pass through its equinox, with Sun passing overhead at the Uranian equator. This configuration will provide the first opportunity in modern times for us to view the entire northern hemisphere of the planet, and our first chance to view how the planetary atmosphere reacts to the change from night to day.
The present SNAPSHOT program is using WFPC2 to monitor the appearance of these two planets, acquiring narrowband optical images that both record the overall structure and probe the atmosphere at different depths.

GO 11196: An Ultraviolet Survey of Luminous Infrared Galaxies in the Local Universe

GO 11235: HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies in the Local Universe

A NICMOS image of the interacting LIRG, NGC 6090 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. These two programs build on a previous ACS survey of 88 systems from the IRAS Revised Bright Galaxy Sample (GO 10592) in the F439W and F814W passbands. Program GO 11196 is using the ACS/SBC and WFPC2 to obtain far- (F140LP) and near- (F218W) UV imaging of 27 galaxies; GO 11235 concentrates on near-infrared H-band NICMOs NIC2 imaging of the galaxy cores. Combined with the previously obtained B- and I-band data, these observations will probe
  • the distribution of star formation activity and the presence of bars and bridges, funneling gas towards active regions
  • the age distribution of star clusters
  • the relationship between star formation and AGN activity
  • correlations between near-infrared emission and the mid-IR structures identified from Spitzer IRAC imaging;
  • the presence of coherent structure, bars or bridges, that might funnel gas into the nuclei;
  • the overall structural properties of the LIRGS as a function of luminosity and environment
The observations will also provide a detailed UV images for a reference sample of nearby galaxies. Observations of several interacting system are scheduled for this week.

Past weeks:
page by Neill Reid, updated 25/8/2008