This week on HST

HST Programs: June 23 - June 29, 2008

Program Number Principal Investigator Program Title Links
11079 Luciana Bianchi, The Johns Hopkins University Treasury Imaging of Star Forming Regions in the Local Group: Complementing the GALEX and NOAO Surveys 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
11110 Stephan McCandliss, The Johns Hopkins University Searching for Lyman alpha Emission from FUSE Lyman Continuum Candidates Abstract
11130 Luis Ho, Carnegie Institution of Washington AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge Paradigm, Part II Abstract
11131 Walter Jaffe, Sterrewacht Leiden Star formation at large radii in cooling flow brightest cluster galaxies Abstract
11136 Michael C. Liu, University of Hawaii Resolving Ultracool Astrophysics with Brown Dwarf Binaries 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
11158 R. Michael Rich, University of California - Los Angeles HST Imaging of UV emission in Quiescent Early-type Galaxies Abstract
11183 Crystal Martin, University of California - Santa Barbara Ultraviolet Imaging of Lyman-Alpha-Selected Galaxies at High Redshift Abstract
11186 Joachim Saur, Universitat zu Koeln Investigation of the spatial and temporal structure of Europa's atmospheric emissisons Abstract
11188 Brian Siana, Jet Propulsion Laboratory First Resolved Imaging of Escaping Lyman Continuum 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
11196 Aaron S. Evans, State University of New York at Stony Brook An Ultraviolet Survey of Luminous Infrared Galaxies in the Local Universe Abstract
11206 Kai G. Noeske, University of California - Santa Cruz At the cradle of the Milky Way: Formation of the most massive field disk galaxies at z>1 Abstract
11210 George Fritz Benedict, University of Texas at Austin The Architecture of Exoplanetary Systems Abstract
11233 Giampaolo Piotto, Universita di Padova Multiple Generations of Stars in Massive Galactic Globular Clusters 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
11341 Jason A. Surace, California Institute of Technology Lower Luminosity AGNs at Cosmologically Interesting Redshifts: SEDs and Accretion Rates of z~0.36 Seyferts Abstract
11498 Amy Simon-Miller, NASA Goddard Space Flight Center 2008 Passage of Jupiter's Great Red Spot and Oval BA Abstract

Some selected highlights

GO 11107: Imaging of Local Lyman Break Galaxy Analogs: New Clues to Galaxy Formation in the Early Universe

Mosaic of HST images of M82, the best-known starburst galaxy Current Big Bang cosmological models predict that the universe should have undergone a global re-ionisation at redshifts between 6 and 20. The first generation of stars is generally tapped as the most likely source of the ionising radiation, perhaps enhanced through merger-stimulated starbursts. Direct observations of those galaxies are not possible at present, although the James Webb Space Telescope is expected to open up observations of these systems. In consequence, there is considerable interest in identifying galaxies at lower redshifts that could serve as analogues for the z>6 systems. Over the last few years, the Galaxy Evolution Explorer (GALEX) has proved an important new tool in identifying candidate objects. GALEX has conducted an all-sky survey at ultraviolet wavelengths, and has uncovered sigificant numbers of UV luminous galaxies at low and moderate redshifts. Many of these galaxies are starbursts, undergoing substantial outbursts of star formation. These galaxies have been categorised as "compact UV luminous galaxies" (UVLGs). These appear to be galaxies that are undergoing small-scale mergers, leading to extensive dissipation and vigorous star formation. The present program is using the ACS/SBC prism and WFPC2 to obtain ultraviolet spectra and R-band images of 31 systems, probing the star formation history and its variation with environment.

GO 11196: An Ultraviolet Survey 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. The present program builds on a previous ACS survey of 88 systems from the IRAS Revised Bright Galaxy Sample (GO 10592) in the F439W and F814W passbands. The present program is using the ACS/SBC and WFPC2 to obtain far- (F140LP) and near- (F218W) UV imaging of 27 galaxies. 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
  • 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 the interacting system, NGC 17, are scheduled for this week.

GO 11233: Multiple Generations of Stars in Massive Galactic Globular Clusters

NGC 2808, a globular cluster with multiple stellar populations Globular clusters are remnants of the first substantial burst of star formation in the Milky Way. With typical masses of a few x 105 solar masses, distributed among several x 106 stars, the standard picture holds that these are simple systems, where all the stars formed in a single starburst and, as a consequence, have the same age and metallicity. Until recently, the only known exception to this rule was the cluster Omega Centauri, which is significantly more massive than most clusters and has both double main sequence and a range of metallicities among the evolved stars. Omega Cen has been joined by at least one more cluster, NGC 2808, which shows evidence for three distinct branches to the main sequence. The origin of this feature is not known, but it may be significant that NGC 2808 is also one of the more massive clusters, and might therefore be able to survive several burst of star formation (or, conversely, be the product of a multi proto-globular merger). The present program aims to use WFPC2 to obtain high-precision photometry of other massive globulars, such as NGC 1851, M80 and M13.

GO 11498: 2008 Passage of Jupiter's Great Red Spot and Oval BA

The Great Red Spot and the white ovaL (HST image) In the late 1930s, bright white clouds expanded and encircled Jupiter's southern hemisphere in a band near 33 degrees south planetographic latitude. Those clouds collapsed into three large anticyclonic storms, later named the White Ovals, that were second in size only to the Great Red Spot, GRS. In the mid to late 1990s these storms suddenly approached each other very closely, resulting in the 1998 merger of two of the storms (hence the designation Oval BA). In 2000, the third oval also merged, leaving one remaining large White Oval. Early in 2006, amateur observers noted that the oval appeared to be changing in appearance and turning red, leading to the feature redesignated as the Little Red Spot - LRS. While small red spots do appear on Jupiter from time to time, they usually form as a colored spot, cloud over, and become white, rather than the opposite. Hubble was used to image the atmospheric features throughout 2006 and 2007. Both the GRS and the LRS shows drifts in longitude, with the GRS drifting westward and the LRS eastward. The two systems pass each other every 2 years and, at that time, the relative wind motions can lead to changes in morphology. The present proposal aims to use WFPC2 to obtain multiwavelength observations during the 2008 passage, studying the vertical structure of the storm, and investigating possible mechanisms that underlie any observed changes in appearance.

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