| Program Number | Principal Investigator | Program Title |
|---|---|---|
| 12488 | Mattia Negrello, Open University | SNAPshot observations of gravitational lens systems discovered via wide-field Herschel imaging |
| 12558 | Nial R. Tanvir, University of Leicester | Identifying and studying gamma-ray bursts at very high redshifts |
| 12791 | Marc Postman, Space Telescope Science Institute | Through a Lens, Darkly - New Constraints on the Fundamental Components of the Cosmos |
| 12816 | David Syphers, University of Colorado at Boulder | Probing the Reionization Epoch of IGM Helium: A Detailed Follow-up Study of Three High-Quality He II Quasars |
| 12870 | Boris T. Gaensicke, The University of Warwick | The mass and temperature distribution of accreting white dwarfs |
| 12874 | David Floyd, Monash University | Quasar accretion disks: is the standard model valid? |
| 12886 | Sanchayeeta Borthakur, The Johns Hopkins University | Direct Detection of Escaping Lyman Continuum Emission from Local Lyman-Break Analog Galaxy |
| 12889 | Sherry H. Suyu, Academia Sinica, Institute of Astronomy and Astrophysics | Accurate Cosmology from Gravitational Lens Time Delays |
| 12897 | Marc W. Buie, Southwest Research Institute | Pluto System Orbits in Support of New Horizons |
| 12898 | Leon Koopmans, Kapteyn Astronomical Institute | Discovering the Dark Side of CDM Substructure |
| 12902 | Matthew A. Malkan, University of California - Los Angeles | WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time |
| 12903 | Luis C. Ho, Carnegie Institution of Washington | The Evolutionary Link Between Type 2 and Type 1 Quasars |
| 12922 | Jong-Hak Woo, Seoul National University | Calibrating black hole mass estimators using the enlarged sample of reverberation-mapped AGNs |
| 12930 | Carrie Bridge, California Institute of Technology | WISE Discovered Ly-alpha Blobs at High-z: The missing link? |
| 12933 | Francesco R. Ferraro, Universita di Bologna | COSMIC-LAB: unveling the true nature of Terzan 5, a pristine fragment of the Galactic bulge |
| 12944 | Katelyn Allers, Bucknell University | A High-Resolution Survey of the Very Youngest Brown Dwarfs |
| 12945 | Gregory Rudnick, University of Kansas Center for Research, Inc. | Spatially Resolved Observations of Gas Stripping in Intermediate Redshift Clusters and Groups |
| 12971 | Harvey B. Richer, University of British Columbia | Completing the Empirical White Dwarf Cooling Sequence: Hot White Dwarfs in 47 Tucanae |
| 12982 | Nicolas Lehner, University of Notre Dame | Are the Milky Way's High Velocity Clouds Fuel for Star Formation or for the Galactic Corona? |
| 13003 | Michael D. Gladders, University of Chicago | Resolving the Star Formation in Distant Galaxies |
| 13021 | Jacob L. Bean, University of Chicago | Revealing the Diversity of Super-Earth Atmospheres |
| 13023 | Marco Chiaberge, Space Telescope Science Institute - ESA | Universe in transition: powerful activity in the Bright Ages |
| 13046 | Robert P. Kirshner, Harvard University | RAISIN: Tracers of cosmic expansion with SN IA in the IR |
| 13050 | Remco van den Bosch, Max-Planck-Institut fur Astronomie, Heidelberg | The Most Massive Black Holes in Small Galaxies |
| 13176 | Daniel Apai, University of Arizona | Extrasolar Storms: The Physics and Chemistry of Evolving Cloud Structures in Brown Dwarf Atmospheres |
| 13197 | Michael F. A'Hearn, University of Maryland | Distant Activity of Comet ISON |
| 13229 | Zolt Levay, Space Telescope Science Institute | Hubble Heritage imaging of Comet ISON |
GO 12488: SNAPshot observations of gravitational lens systems discovered via wide-field Herschel imaging
ACS images of galaxy-galaxy Einstein ring lenses from the Sloan survey |
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 primarily to probe the mass distribution of galaxy clusters, using theoretical models to analyse the arcs and arclets that are produced by strong lensing of background galaxies, and the large-scale mass distribution, through analysis of weak lensing effects on galaxy morphologies. Gravitational lensing can also be used to investigate the mass distribution of individual galaxies. Until recently, the most common background sources that were being detected and investigates were quasars. Galaxy-galaxy lenses, however, offer a distinct advantage, since the background source is extended, and therefore imposes a stronger constraints on the mass distribution of the lensing galaxy than a point-source QSO. HST has carried out a number of programs following up candidate lenses identified from the Sloan Digital Sky Survey (eg GO 10886 , GO 11289 , GO 12210 ). The present program is using WFCE on HST to obtain follow-up near-infrared (F110W) images of up to 200 candidate lenses selected from the Herschel Astrophysical Terahertz Large Area (H-ATLAS) and the Herschel Multi-tiered Extra-galactic (HerMES) surveys. The HST data will verify the nature of those candidates, and provide the angular resolution necessary to model the mass distribution. |
GO 12897: Pluto system orbits in support of New Horizons
Hubble Space Telescope images of the Pluto system, including the recently discovered moons, P4 and P5 |
Pluto, one of the largest members of the Kuiper Belt and, until recently, the outermost planet in the solar system, has been in the news over the last year or two. Besides the extended "planet"/"dwarf planet" debate, Pluto is the primary target of the New Horizons Mission. In 1978, James Christy discovered from analyses of photographic plates that Pluto has a relatively large companion moon, Charon, with a diameter of ~1200 km, or almost half that of Pluto itself. In 2005, Hubble observations led to the discovery of two small moons, christened Nix and Hydra. These two new moons are 5,000 fainter than Pluto itself, implying diameters as small as ~30-50 km if the surface composition is similar to Pluto itself. Over the past two years, a series of observations were taken in support of the New Horizons mission, using WFC3 to search for faint rings due to dust particles that might jeopardise the space craft and require a course correction. While no rings were detected unequivocally, two small satellite, christened "P4" and "P5", have been discovered. Both are significantly fainter than Nix and Hydra, and may well be as small as 10-13 km in size. There is also some evidence that might point to the presence of a debris ring within Charon's orbit. The present observations, again in support of New Horizons, will use WFC3 to push to even fainter magnitudes to both better characterise the P4 and P5 orbits and search for even fainter moons. |
GO 12903:: The Evolutionary Link Between Type 2 and Type 1 Quasars
Artist's impression of the black hole and surrounding torus in an AGN |
This year (2013) is the fiftieth anniversary of the recognition that QSOs (quasars, quasi-stellar objects) were extremely luminous objects lying at substantial redshifts. The central engine powering these luminous objects is now recognised as a supermassive black hole, marking the central regions of a galaxy. As such, QSOs are clearly related to (and more luminous than) active galactic nuclei (AGN). Like AGNs, QSOs have been segregated into two categories based on their spectral properties: systems with broad lines are characterised as Type 1 QSOs; systems with narrow lines are classed as Type 2. As with AGN, the underlying cause of these differences is generally believed to reside more in our perspective than on the sources themselves: heavily obscured systems, where the central accretion disk lies behind a thick veil of dust, are observed as Type 2 systems; they are expected to evolve to form Type 1 systems as the dust is ablated and destroyed. The present SNAP program aims to test this scenario by coupling mid-infrared Herschel observations, probing the dust environment, with HST near-infrared WFC3 imaging of targets drawn from two matched samples of Type 1 and Type 2 QSOs. |
GO 13176: Extrasolar Storms: The Physics and Chemistry of Evolving Cloud Structures in Brown Dwarf Atmospheres
Brown dwarfs are likely to have complex atmospheric structures that resemble Jupiter |
Brown dwarfs are failed stars - objects that form like stars, by gravitational collapse within giant molecular clouds, but which have insufficient mass to raise the central temperature above 107 K, and which therefore are unable to ignite hydrogran fusion and maintain a long-lived central energy source. As such, these objects reach a maximum surface temperature of perhaps 3,000K some tens of millions of years after their formation, and subsequently cool and fade into oblivion. As they cool, they move through spectral types M, L and T, with the oldest brown dwarfs now likely to have temperatures close to 300K and emergent spectra characterised by water and ammonia bands, the putative signatures of the spectral class Y. As these dwarfs cool from L to T (~1500 to ~1200K), the atmospheres undergo significant changes, with heavier elements condensing to form dust. That dust can form clouds, perhaps giving the dwarf's surface a banded appearance, similar to Jupiter. The clouds themselves may appear and disappear over relatively short timescales, leading to photometric variations at particular wavelengths. Past programs have used both Spitzer and HST to monitor spectral variability in a number of systems. The present program aimes to broaden the sample by targeting six known variable for time-resolved WFC3 grism spectroscopy. All of the targets will also be obsreved with Spitzer. |