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41.
O. Reimer P. F. Michelson R. A. Cameron S. W. Digel D. J. Thompson K. S. Wood 《Astrophysics and Space Science》2007,309(1-4):523-526
Gamma-ray astrophysics depends in many ways on multiwavelength studies. The Gamma-ray Large Area Space Telescope (GLAST) Large
Area Telescope (LAT) Collaboration has started multiwavelength planning well before the scheduled 2007 launch of the observatory.
Some of the high-priority multiwavelength needs include: (1) availability of contemporaneous radio and X-ray timing of pulsars;
(2) expansion of blazar catalogs, including redshift measurements; (3) improved observations of molecular clouds, especially
at high galactic latitudes; (4) simultaneous broad-band blazar monitoring; (5) characterization of gamma-ray transients, including
gamma ray bursts; (6) radio, optical, X-ray and TeV counterpart searches for reliable and effective sources identification
and characterization. Several of these activities are needed to be in place before launch.
相似文献
42.
Pim de Klerk Andreas Haberl Andreas Kaffke Matthias Krebs Izolda Matchutadze Merten Minke Jenny Schulz Hans Joosten 《Quaternary Science Reviews》2009,28(9-10):890-910
The Kolkheti lowlands of western Georgia have a unique vegetation and a rich cultural history. Palynological and macrofossil analysis accompanied by AMS 14C-dates of the deposits of the Ispani 2 mire near Kobuleti allow the reconstruction of regional vegetation, environmental history and local peatland development within the context of Black Sea level and cultural changes. Comparison of two adjacent peatland cores confirms spatial differences in wetland development. Prior to 5400 cal yr BP, the Ispani basin was a floodplain of an active river system where overbank deposits with fluvially transported Castanea pollen were deposited. Subsequently, a lake or lagoon developed in which reeds expanded. These were succeeded by herb-rich open alder carrs. After 1900 cal yr BP, Carpinus and Fagus expanded on the dry grounds, where formerly Quercus was more abundant. Also Castanea declined. Local reedbeds, that burned regularly, succeeded the alder carr. After 1000 cal yr BP, a percolation bog developed resulting in the formation of 4 m of loose, porous, and largely undecomposed Sphagnum austinii peat with Molinia roots. The upper 50 cm of the analysed section show extensive human impact on the landscape during the 20th century. 相似文献
43.
We use the Hubble Ultra Deep Field to study the galaxy luminosity–size ( M – R e ) distribution. With a careful analysis of selection effects due to both detection completeness and measurement reliability, we identify bias-free regions in the M – R e plane for a series of volume-limited samples. By comparison to a nearby survey also having well-defined selection limits, namely the Millennium Galaxy Catalogue, we present clear evidence for evolution in surface brightness since z ∼ 0.7 . Specifically, we demonstrate that the mean, rest-frame B -band 〈μ〉 e for galaxies in a sample spanning 8 mag in luminosity between M B =−22 and −14 mag increases by ∼1.0 mag arcsec−2 from z ∼ 0.1 to 0.7. We also highlight the importance of considering surface brightness-dependent measurement biases in addition to incompleteness biases. In particular, the increasing, systematic underestimation of Kron fluxes towards low surface brightnesses may cause diffuse, yet luminous, systems to be mistaken for faint, compact objects. 相似文献
44.
WASP-1b and WASP-2b: two new transiting exoplanets detected with SuperWASP and SOPHIE 总被引:1,自引:0,他引:1
A. Collier Cameron F. Bouchy G. Hébrard P. Maxted D. Pollacco F. Pont I. Skillen B. Smalley R. A. Street R. G. West D. M. Wilson S. Aigrain D. J. Christian W. I. Clarkson B. Enoch A. Evans A. Fitzsimmons M. Fleenor M. Gillon C. A. Haswell L. Hebb C. Hellier S. T. Hodgkin K. Horne J. Irwin S. R. Kane F. P. Keenan B. Loeillet T. A. Lister M. Mayor C. Moutou A. J. Norton J. Osborne N. Parley D. Queloz R. Ryans A. H. M. J. Triaud S. Udry P. J. Wheatley 《Monthly notices of the Royal Astronomical Society》2007,375(3):951-957
We have detected low-amplitude radial-velocity variations in two stars, USNO-B1.0 1219–0005465 (GSC 02265–00107 = WASP–1 ) and USNO-B1.0 0964–0543604 (GSC 00522–01199 = WASP–2 ). Both stars were identified as being likely host stars of transiting exoplanets in the 2004 SuperWASP wide-field transit survey. Using the newly commissioned radial-velocity spectrograph SOPHIE at the Observatoire de Haute-Provence, we found that both objects exhibit reflex orbital radial-velocity variations with amplitudes characteristic of planetary-mass companions and in-phase with the photometric orbits. Line-bisector studies rule out faint blended binaries as the cause of either the radial-velocity variations or the transits. We perform preliminary spectral analyses of the host stars, which together with their radial-velocity variations and fits to the transit light curves yield estimates of the planetary masses and radii. WASP-1b and WASP-2b have orbital periods of 2.52 and 2.15 d, respectively. Given mass estimates for their F7V and K1V primaries, we derive planet masses 0.80–0.98 and 0.81–0.95 times that of Jupiter, respectively. WASP-1b appears to have an inflated radius of at least 1.33 R Jup , whereas WASP-2b has a radius in the range 0.65–1.26 R Jup . 相似文献
45.
A global positioning system and ground penetrating radar surveys is used to produce digital elevation models of the surface and bed of Brewster Glacier. These are used to derive maps of subglacial hydraulic potential and drainage system structure using three different assumptions about the subglacial water pressure (Pw): (i) Pw = ice overburden; (ii) Pw = half ice overburden; (iii) Pw = atmospheric. Additionally, 16 dye‐tracing experiments at 12 locations were performed through a summer melt season. Dye return curve shape, together with calculations of transit velocity, dispersivity and storage, are used to infer the likely morphology of the subglacial drainage system. Taken together, the data indicate that the glacier is underlain by a channelised but hydraulically inefficient drainage system in the early summer in which water pressures are close to ice overburden. By mid‐summer, water pressures are closer to half‐ice overburden and the channelised drainage system is more hydraulically efficient. Surface streams that enter the glacier close to the location of major subglacial drainage pathways are routed quickly to the channels and then to the glacier snout. Streams that enter the glacier further away from the drainage pathways are routed slowly to the channels and then to the snout because they first flow through a distributed drainage system. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
46.
Journal of Geographical Systems - Auckland, the largest city of New Zealand, is one of the most diverse cities in the world, with more than 40% of its population born abroad, more than 200... 相似文献
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48.
Chris A. Mattmann Duane Waliser Jinwon Kim Cameron Goodale Andrew Hart Paul Ramirez Dan Crichton Paul Zimdars Maziyar Boustani Kyo Lee Paul Loikith Kim Whitehall Chris Jack Bruce Hewitson 《Earth Science Informatics》2014,7(1):1-12
The Regional Climate Model Evaluation System (RCMES) facilitates the rapid, flexible inclusion of NASA observations into climate model evaluations. RCMES provides two fundamental components. A database (RCMED) is a scalable point-oriented cloud database used to elastically store remote sensing observations and to make them available using a space time query interface. The analysis toolkit (RCMET) is a Python-based toolkit that can be delivered as a cloud virtual machine, or as an installer package deployed using Python Buildout to users in order to allow for temporal and spatial regridding, metrics calculation (RMSE, bias, PDFs, etc.) and end-user visualization. RCMET is available to users in an “offline”, lone scientist mode based on a virtual machine dynamically constructed with model outputs and observations to evaluate; or on an institution’s computational cluster seated close to the observations and model outputs. We have leveraged RCMES within the content of the Coordinated Regional Downscaling Experiment (CORDEX) project, working with the University of Cape Town and other institutions to compare the model output to NASA remote sensing data; in addition we are also working with the North American Regional Climate Change Assessment Program (NARCCAP). In this paper we explain the contribution of cloud computing to RCMES’s specifically describing studies of various cloud databases we evaluated for RCMED, and virtualization toolkits for RCMET, and their potential strengths in delivering user-created dynamic regional climate model evaluation virtual machines for our users. 相似文献
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