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: http://www.stsci.edu/~inr/thisweek1/2013/thisweek077.html
Дата изменения: Fri Nov 15 23:28:08 2013 Дата индексирования: Sat Mar 1 13:24:31 2014 Кодировка: Поисковые слова: cygnus |
Program Number | Principal Investigator | Program Title |
---|---|---|
12473 | David Kent Sing, University of Exeter | An Optical Transmission Spectral Survey of hot-Jupiter Exoplanetary Atmospheres |
12488 | Mattia Negrello, Open University | SNAPshot observations of gravitational lens systems discovered via wide-field Herschel imaging |
12555 | Robert Louis da Silva, University of California - Santa Cruz | On the Triggering of Quasars During First Passage |
12577 | Armin Rest, Space Telescope Science Institute | Spectral Time Series of the Cas A Supernova |
12584 | Amy E. Reines, Associated Universities, Inc. | Confirming the First Supermassive Black Hole in a Dwarf Starburst Galaxy |
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? |
12880 | Adam Riess, The Johns Hopkins University | The Hubble Constant: Completing HST's Legacy with WFC3 |
12889 | Sherry H. Suyu, Academia Sinica, Institute of Astronomy and Astrophysics | Accurate Cosmology from Gravitational Lens Time Delays |
12893 | Ronald L Gilliland, The Pennsylvania State University | Study of Small and Cool Kepler Planet Candidates with High Resolution Imaging |
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 |
12906 | Klaus Werner, Eberhard Karls Universitat, Tubingen | Chemical composition of an exo-planetary debris disk |
12924 | Nathan Smith, University of Arizona | Measuring the Wind Properties of a Galactic SN1987A analog with COS |
12930 | Carrie Bridge, California Institute of Technology | WISE Discovered Ly-alpha Blobs at High-z: The missing link? |
12935 | Martin A. Guerrero, Instituto de Astrofisica de Andalucia (IAA) | Witnessing the Expansion of Hydrogen-Poor Ejecta in Born-Again Planetary Nebulae |
12938 | Sergio B. Dieterich, Georgia State University Research Foundation | Probing Fundamental Stellar Parameters with HST/STIS Spectroscopy of M Dwarf Binaries |
12942 | Eilat Glikman, Yale University | Testing the Merger Hypothesis for Black Hole/Galaxy Co-Evolution at z~2 |
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 |
12949 | Daniel Perley, California Institute of Technology | Unveiling the Dusty Universe with the Host Galaxies of Obscured GRBs |
12951 | Aida H. Wofford, Space Telescope Science Institute | Do Lyman-alpha photons escape from star-forming galaxies through dust-holes? |
12977 | Ivana Damjanov, Smithsonian Institution Astrophysical Observatory | Local Turbulent Disks: analogs of high-redshift vigorously star-forming disks and laboratories for galaxy assembly? |
12982 | Nicolas Lehner, University of Notre Dame | Are the Milky Way's High Velocity Clouds Fuel for Star Formation or for the Galactic Corona? |
13007 | Lee Armus, California Institute of Technology | UV Imaging of Luminous Infrared Galaxies in the GOALS Sample |
13024 | John S. Mulchaey, Carnegie Institution of Washington | A Public Snapshot Survey of Galaxies Associated with O VI and Ne VIII Absorbers |
13025 | Andrew J. Levan, The University of Warwick | Unveiling the progenitors of the most luminous supernovae |
13027 | Goeran Oestlin, Stockholm University | Escape of Lyman photons from Tololo 1247-232 |
13032 | Carol A. Grady, Eureka Scientific Inc. | Crossing the Snow Line: Mapping Ice Photodesorption products in the Disks of Herbig Ae-Fe stars |
13033 | Jason Tumlinson, Space Telescope Science Institute | COS-Halos: New FUV Measurements of Baryons and Metals in the Inner Circumgalactic Medium |
13034 | Jon Mauerhan, University of Arizona | A Homunculus Around the Star NaSt1 {WR122}? |
13046 | Robert P. Kirshner, Harvard University | RAISIN: Tracers of cosmic expansion with SN IA in the IR |
13060 | Thomas R. Ayres, University of Colorado at Boulder | Alpha Cen: Climbing out of a Coronal Recession? {year 2 continuation} |
13062 | Howard E. Bond, Space Telescope Science Institute | HST Observations of Astrophysically Important Visual Binaries |
13063 | Adam Riess, The Johns Hopkins University | Supernova Follow-up for MCT |
13112 | Xin Liu, University of California - Los Angeles | The Hierarchical Assembly of Massive Black Holes: Identifying Kpc-Scale Triple AGNs with Chandra, HST, and EVLA |
13178 | J. Davy Kirkpatrick, California Institute of Technology | Spitzer Trigonometric Parallaxes of the Solar Neighborhood's Coldest Brown Dwarfs |
GO 12893: Study of Small and Cool Kepler Planet Candidates with High Resolution Imaging
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Kepler is a NASA Discovery-class mission, designed to search for extrasolar planets by using high-precision photometric observations to detect transits. Launched on 7 March 2009, Kepler continuously monitors ~100,000 (mainly) solar-type stare within a ~100 square degree region in Cygnus. The mission has been an astounding success. Ground-based observations have successfully detected a couple of dozen transiting planets (e.g. HD 209458); almost all are "hot jupiters", gas giants on short-period orbits which produce a photometric dip of ~10-2 with a periopd of a few days, with a smattering of neptune-sized "super-Earths". Kepler, in contrast, has so far identified 1,790 exoplanet host stars and a total of 2,321 transiting exoplanets. More significantly, the exquisite precision of Kepler's photometric observations enables it to detect the 0.01% transit signature of earth analogues in these systems. A subset of stellar binaries provide one of the main sources of confusion in searching for planetary transits, since "grazing" transits can mimic the planetary signature. This is particularly an issue with Kepler, since the optical system is designed to provide a broad psf, spreading the stellar flux over a large area on the detector to allow high photometric accuracy. As a result, faint eclipsing stellar binaries will contribute to the source counts. Moreover, since the target field is (intentionally) within the Milky Way, there is a significant potential for unresolved stars within the (relatively broad) Kepler psf to increase the total signal, and hence dilute the depth of transits, giving the appearance of a smaller diameter exoplanet. This program is using the high spatial resolution imaging provided by HST to study a subset of the Kepler Earth-like candidates to assess the potential of this effect. |
GO 12930: WISE Discovered Ly-alpha Blobs at High-z: The missing link?
GO 12942: Testing the Merger Hypothesis for Black Hole/Galaxy Co-Evolution at z~2
GO 13178: Spitzer Trigonometric Parallaxes of the Solar Neighborhood's Coldest Brown Dwarfs
![]() The stellar menagerie: Sun to Jupiter, via brown dwarfs |
Brown dwarfs are objects that form in the same manner as stars, by gravitational collapse within molecular clouds, but which do not accrete sufficient mass to raise the central temperature above ~2 million Kelvin and ignite hydrogen fusion. As a result, these objects, which have masses less than 0.075 MSun or ~75 M<\sub>Jup, lack a sustained source of energy, and they fade and cool on relatively short astronomical (albeit, long anthropological) timescales. Following their discovery over a decade ago, considerable observational and theoretical attention has focused on the evolution of their intrinsic properties, particularly the details of the atmospheric changes. At their formation, most brown dwarfs have temperatures of ~3,000 to 3,500K, comparable with early-type M dwarfs, but they rapidly cool, with the rate of cooling increasing with decreasing mass. As temperatures drop below ~2,000K, dust condenses within the atmosphere, molecular bands of titanium oxide and vanadium oxide disappear from the spectrum to be replaced by metal hydrides, and the objects are characterised as spectral type L. Below 1,300K, strong methane bands appear in the near-infrared, characteristics of spectral type T. At present, the coolest T dwarfs known have temperatures of ~650 to 700K. At lower temperatures, other species, notably ammonia, are expected to become prominent, and a number of efforts have been undertaken recently to find examples of these "Y" dwarfs. The search is complicated by the fact that such objects are extremely faint instrinsically, so only the nearest will be detectable. Identifying such ultra-ultracool dwarfs was a goal of the WISE satellite mission, which recently completed its all-sky survey. WISE has succeeded in identifying close to a dozen very red, and therefore very cool, stellar sources. Initial follow-up observations with both Spitzer and HST suggest that at least may have effective temperatures less than 400K, although subsequent analyses suggests that those temperatures may be udnerestimated. These are the first examples of the new spectral class of Y dwarfs. The present program follows up on the initial discoveries by combining astrometry from Spitzer imaging, deriving proper motions and parallaxes, with low-resolution spectroscopy with the G102 and G141 grisms on WFC3-IR. The overall goal is to establish reliable distances, luminosities and temperatures, defining these sources as benchmarks in the lowest reaches of the brown dwarf regime. |