This week on HST


HST Programs: November 1, 2010 - November 7, 2010

Program Number Principal Investigator Program Title
11563 Garth D. Illingworth, University of California - Santa Cruz Galaxies at z~7-10 in the Reionization Epoch: Luminosity Functions to <0.2L* from Deep IR Imaging of the HUDF and HUDF05 Fields
11585 Neil H. Crighton, University of Durham Tracing the distribution of gas and galaxies using three closely-spaced background QSOs
11597 S. Adam Stanford, University of California - Davis Spectroscopy of IR-Selected Galaxy Clusters at 1 < z < 1.5
11663 Mark Brodwin, Smithsonian Institution Astrophysical Observatory Formation and Evolution of Massive Galaxies in the Richest Environments at 1.5 < z < 2.0
11694 David R. Law, University of California - Los Angeles Mapping the Interaction between High-Redshift Galaxies and the Intergalactic Environment
11702 Hao-Jing Yan, The Ohio State University Search for Very High-z Galaxies with WFC3 Pure Parallel
11721 Richard S. Ellis, California Institute of Technology Verifying the Utility of Type Ia Supernovae as Cosmological Probes: Evolution and Dispersion in the Ultraviolet Spectra
11732 C. S. Kochanek, The Ohio State University The Temperature Profiles of Quasar Accretion Disks
11830 Rita M. Sambruna, NASA Goddard Space Flight Center Jets at Intermediate Redshifts: Shedding Light on Emission Mechanisms and Physics
11831 Preeti Kharb, Rochester Institute of Technology Probing X-Ray Jet Emission Mechanisms in a Complete Blazar Sample
12019 Christy A. Tremonti, University of Wisconsin - Madison After the Fall: Fading AGN in Post-starburst Galaxies
12099 Adam Riess, The Johns Hopkins University Supernova Follow-up for MCT
12166 Harald Ebeling, University of Hawaii A Snapshot Survey of The Most Massive Clusters of Galaxies
12178 Scott F. Anderson, University of Washington Spanning the Reionization History of IGM Helium: a Highly Efficient Spectral Survey of the Far-UV-Brightest Quasars
12184 Xiaohui Fan, University of Arizona A SNAP Survey for Gravitational Lenses Among z~6 Quasars
12197 Johan Richard, University of Durham Evolution in the Size-Luminosity Relation of HII regions in Gravitationally-lensed galaxies
12203 S. Adam Stanford, University of California - Davis Rest Frame Optical Spectroscopy of Galaxy Clusters at 1.6 < z < 1.9
12209 Adam S. Bolton, University of Utah A Strong Lensing Measurement of the Evolution of Mass Structure in Giant Elliptical Galaxies
12210 Adam S. Bolton, University of Utah SLACS for the Masses: Extending Strong Lensing to Lower Masses and Smaller Radii
12213 Roelof S. de Jong, Astrophysikalisches Institut Potsdam The Stellar Halo Profiles of Massive Disk Galaxies
12214 Sara Ellison, University of Victoria Low redshift damped Lyman alpha systems selected by 21cm absorption: A new route to high efficiency?
12215 Nancy R. Evans, Smithsonian Institution Astrophysical Observatory Searching for the Missing Low-Mass Companions of Massive Stars
12229 Linda J. Smith, Space Telescope Science Institute HST U-band Survey of Star Clusters in Nearby Star-Forming Galaxies
12234 Wesley Fraser, California Institute of Technology Differentiation in the Kuiper belt: a search for silicates on icy bodies.
12275 Bart P. Wakker, University of Wisconsin - Madison Measuring gas flow rates in the Milky Way
12289 J. Christopher Howk, University of Notre Dame A COS Snapshot Survey for z < 1.25 Lyman Limit Systems
12291 John Krist, Jet Propulsion Laboratory STIS coronagraphy of Spitzer-selected debris disks
12292 Tommaso L. Treu, University of California - Santa Barbara SWELLS: doubling the number of disk-dominated edge-on spiral lens galaxies
12312 Harold A. Weaver, The Johns Hopkins University Applied Physics Laboratory Hubble Investigation of 103P/Hartley 2 in Support of NASA's DIXI Mission
12324 C. S. Kochanek, The Ohio State University The Temperature Profiles of Quasar Accretion Disks
12326 Keith S. Noll, Space Telescope Science Institute Hubble Heritage 2.0
12328 Pieter van Dokkum, Yale University 3D-HST: A Spectroscopic Galaxy Evolution Treasury Part 2

Selected highlights

GO 11563: Galaxies at z~7-10 in the Reionization Epoch: Luminosity Functions to <0.2L* from Deep IR Imaging of the HUDF and HUDF05 Fields

The ACS optical/far-red image of the Hubble Ultra Deep Field Galaxy evolution in the early Universe is a discipline of astronomy that has been transformed by observations with the Hubble Space Telescope. The original Hubble Deep Field, the product of 10 days observation in December 1995 of a single pointing of Wide Field Planetary Camera 2, demonstrated conclusively that galaxy formation was a far from passive process. The images revealed numerous blue disturbed and irregular systems, characteristic of star formation in galaxy collisions and mergers. Building on this initial progam, the Hubble Deep Field South (HDFS) provided matching data for a second southern field, allowing a first assessment of likely effects due to field to field cosmic variance, and the Hubble Ultra-Deep Field (UDF) probed to even fainter magitude with the Advanced Camera for Surveys (ACS). The highest redshift objects found in the UDF have redshifts approaching z~7. Pushing to larger distances, and greater ages, demands observatons at near-infrared wavelengths, as the characteristics signatures of star formation are driven further redward in the spectrum. The present program aims to extend observations beyond z~8 to z+9 or even 10 by using the WFC3-IR camera to obtain deep F850LP (Y), F105W (J) and F160W (H) images centred on the UDF and two flanking fields. Parallel observations with ACS are being used to extend the visible and red imaging data to even fainter magitudes.

GO 11732: The Temperature Profiles of Quasar Accretion Disks

The first Einstein cross, the gravitational lensed QSO, G2237+0305 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 to probe the mass distributions on a variety of scales: of galaxies (primarily via multiply-imaged quasars); of galaxy clusters (arcs and arclets); and at the largest scales (weak lensing). However, lensing can also provide insight on the small-scale properties of the object being lensed. In a lensed QSO, the light from the QSO follows different paths to produce the separate images; each of those paths has a different length; consequently, flux variations in the source show up at different times in the separate images. The present program aims to take advantage of this property to probe the structure of the accretion disks surrounding the central black hole in a number of lensed QSOs. The program will combine ultraviolet observations with the WFC3/UVIS camera on HST with GALEX UV data for 5 lenses spanning as broad range of black hole masses. Studying the variation as a function of wavelength should probe the accretion disk structure, since light from the inner regions are expected to dominate at shorter wavelengths, while the outer regions dominate at longer wavelengths.

GO 12019: After the Fall: Fading AGN in Post-starburst Galaxies

An artist's rendition of the central accretion disk and jet of an AGN Observational investigations over the past decade or more have shown that many, probably most, spiral galaxies harbour a massive black hole within their central regions. In some systems, that black hole can lead to notable activity. Active systems (AGNs) are characterised by the presence of strong emission lines of numerous species, including H, He I, He II, and Fe, Ca, O, C and S over a range of ionisations. Those features originate from gas clouds in the nuclear regions, with the energy supplied through accretion onto a central massive black hole. The high-temperature, rapidly-rotating gas clouds nearest the central engine are responsible for producing broad emission lines (hence, the "Broad Line Region"). That activity is often linked with ongoing star formation. The present progrma aims to target 12 massive post-starburst galaxies at redshifts between z=0.4 and z=0.8, combining HST and Chandra observations. The aim is to probe star formation and black-hole accretion, and investigate the coupling between the two processes.

GO 12178: Spanning the Reionization History of IGM Helium: a Highly Efficient Spectral Survey of the Far-UV-Brightest Quasars

GALEX image of the nearby spiral, M81 The reionisation epoch for intergalactic helium is thought to occur somewhere between redshifts 3 and 4. Observations with the GALEX satellite, a NASA small explorer-class mission equipped with a 50-cm diameter telescope, are proving critical in testing this hypothesis through the identification of UV bright quasars in the appropriate redshift range. Galex was launched on 28th April 2003, and continues to operate more than 30 months beyond its nominal lifetime, conducting ultraviolet imaging and low-resolution grism spectroscopy at far-UV (125-175 nm) and near-UV (175-280 nm) wavelengths. Past HST programs by this research have used the ACS/SBC to target sources identified by cross-referencing GALEX against SDSS catalogues of moderate (1 < z < 3) and high redshift (z > 3.1) quasars. These sources can serve as effective probes of the ionisation state of the intergalactic medium at intervening redshifts. In particular, analysis of the He II Lyman-alpha absorption will shed light on the epoch of reionisation of intergalactic helium, generall placed between redshifts 3 and 4. The present program will use the ACS/SBC PR120L prism for spectroscopy of 40 QSOs with redshifts in the range 3.1 < z < 5.1.

Past weeks:
page by Neill Reid, updated 12/11/2010