Institution
Goddard Space Flight Center
Facility•Greenbelt, Maryland, United States•
About: Goddard Space Flight Center is a facility organization based out in Greenbelt, Maryland, United States. It is known for research contribution in the topics: Galaxy & Solar wind. The organization has 19058 authors who have published 63344 publications receiving 2786037 citations. The organization is also known as: GSFC & Space Flight Center.
Topics: Galaxy, Solar wind, Magnetosphere, Stars, Population
Papers published on a yearly basis
Papers
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TL;DR: The framework and the adaptive algorithms enable physics-based space weather modeling and even short-term forecasting and the algorithms of BATL, the Block-Adaptive Tree Library, are described and its efficiency and scaling properties for various problems are described.
693 citations
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Max Planck Society1, Columbia University2, University of Oslo3, Centre national de la recherche scientifique4, Met Office5, Goddard Space Flight Center6, National Center for Atmospheric Research7, University of Maryland, Baltimore County8, Pacific Northwest National Laboratory9, Geophysical Fluid Dynamics Laboratory10, Utrecht University11, Dalhousie University12, University of Michigan13, ETH Zurich14, Kyushu University15
TL;DR: The AeroCom exercise as mentioned in this paper diagnoses multi-component aerosol modules in global modeling and compares simulated global distributions for mass and mid-visible aerosol optical thickness (aot) among 20 different modules.
Abstract: The AeroCom exercise diagnoses multi-component aerosol modules in global modeling. In an initial assessment simulated global distributions for mass and mid-visible aerosol optical thickness (aot) were compared among 20 different modules. Model diversity was also explored in the context of previous comparisons. For the component combined aot general agreement has improved for the annual global mean. At 0.11 to 0.14, simulated aot values are at the lower end of global averages suggested by remote sensing from ground (AERONET ca. 0.135) and space (satellite composite ca. 0.15). More detailed comparisons, however, reveal that larger differences in regional distribution and significant differences in compositional mixture remain. Of particular concern are large model diversities for contributions by dust and carbonaceous aerosol, because they lead to significant uncertainty in aerosol absorption (aab). Since aot and aab, both, influence the aerosol impact on the radiative energy-balance, the aerosol (direct) forcing uncertainty in modeling is larger than differences in aot might suggest. New diagnostic approaches are proposed to trace model differences in terms of aerosol processing and transport: These include the prescription of common input (e.g. amount, size and injection of aerosol component emissions) and the use of observational capabilities from ground (e.g. measurements networks) or space (e.g. correlations between aerosol and clouds).
692 citations
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Brown University1, Johns Hopkins University Applied Physics Laboratory2, California Institute of Technology3, Smithsonian Institution4, University of Paris-Sud5, Ames Research Center6, Washington University in St. Louis7, Space Science Institute8, Denver Federal Center9, Arizona State University10, Goddard Space Flight Center11, United States Geological Survey12
TL;DR: The diversity of phyllosilicate mineralogy is expanded with the identification of kaolinite, chlorite and illite or muscovite, and a new class of hydrated silicate (hydrated silica).
Abstract: Phyllosilicates, a class of hydrous mineral first definitively identified on Mars by the OMEGA (Observatoire pour la Mineralogie, L'Eau, les Glaces et l'Activitie) instrument, preserve a record of the interaction of water with rocks on Mars. Global mapping showed that phyllosilicates are widespread but are apparently restricted to ancient terrains and a relatively narrow range of mineralogy (Fe/Mg and Al smectite clays). This was interpreted to indicate that phyllosilicate formation occurred during the Noachian (the earliest geological era of Mars), and that the conditions necessary for phyllosilicate formation (moderate to high pH and high water activity) were specific to surface environments during the earliest era of Mars's history. Here we report results from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) of phyllosilicate-rich regions. We expand the diversity of phyllosilicate mineralogy with the identification of kaolinite, chlorite and illite or muscovite, and a new class of hydrated silicate (hydrated silica). We observe diverse Fe/Mg-OH phyllosilicates and find that smectites such as nontronite and saponite are the most common, but chlorites are also present in some locations. Stratigraphic relationships in the Nili Fossae region show olivine-rich materials overlying phyllosilicate-bearing units, indicating the cessation of aqueous alteration before emplacement of the olivine-bearing unit. Hundreds of detections of Fe/Mg phyllosilicate in rims, ejecta and central peaks of craters in the southern highland Noachian cratered terrain indicate excavation of altered crust from depth. We also find phyllosilicate in sedimentary deposits clearly laid by water. These results point to a rich diversity of Noachian environments conducive to habitability.
692 citations
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Johns Hopkins University1, University of Colorado Boulder2, University of Hawaii3, Herzberg Institute of Astrophysics4, Princeton University5, University of California, Berkeley6, Goddard Space Flight Center7, University of Wisconsin-Madison8, Institut d'Astrophysique de Paris9, University College London10, University of Chicago11, Computer Sciences Corporation12, University of Victoria13, Space Telescope Science Institute14
TL;DR: The Far Ultraviolet Spectroscopic Explorer (FUSSE Explorer) satellite observes light in the far-ultraviolet spectral region, 905-1187 Angstrom, with a high spectral resolution as discussed by the authors.
Abstract: The Far Ultraviolet Spectroscopic Explorer satellite observes light in the far-ultraviolet spectral region, 905-1187 Angstrom, with a high spectral resolution The instrument consists of four co-aligned prime-focus telescopes and Rowland spectrographs with microchannel plate detectors Two of the telescope channels use Al :LiF coatings for optimum reflectivity between approximately 1000 and 1187 Angstrom, and the other two channels use SiC coatings for optimized throughput between 905 and 1105 Angstrom The gratings are holographically ruled to correct largely for astigmatism and to minimize scattered light The microchannel plate detectors have KBr photocathodes and use photon counting to achieve good quantum efficiency with low background signal The sensitivity is sufficient to examine reddened lines of sight within the Milky Way and also sufficient to use as active galactic nuclei and QSOs for absorption-line studies of both Milky Way and extragalactic gas clouds This spectral region contains a number of key scientific diagnostics, including O VI, H I, D I, and the strong electronic transitions of H-2 and HD
692 citations
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TL;DR: In this paper, a power-law photon spectrum with an index of -(2.10 ± 0.03) in the 30 MeV to 100 GeV energy range was obtained for the extragalactic high-energy gamma-ray emission.
Abstract: The all-sky survey in high-energy gamma rays (E > 30 MeV) carried out by EGRET aboard the Compton Gamma Ray Observatory provides a unique opportunity to examine in detail the diffuse gamma-ray emission. The observed diffuse emission has a Galactic component arising from cosmic-ray interactions with the local interstellar gas and radiation, as well as an almost uniformly distributed component that is generally believed to originate outside the Galaxy. Through a careful study and removal of the Galactic diffuse emission, the flux, spectrum, and uniformity of the extragalactic emission are deduced. The analysis indicates that the extragalactic emission is well described by a power-law photon spectrum with an index of -(2.10 ± 0.03) in the 30 MeV to 100 GeV energy range. No large-scale spatial anisotropy or changes in the energy spectrum are observed in the deduced extragalactic emission. The most likely explanation for the origin of this extragalactic high-energy gamma-ray emission is that it arises primarily from unresolved gamma-ray-emitting blazars.
690 citations
Authors
Showing all 19247 results
Name | H-index | Papers | Citations |
---|---|---|---|
Anton M. Koekemoer | 168 | 1127 | 106796 |
Alexander S. Szalay | 166 | 936 | 145745 |
David W. Johnson | 160 | 2714 | 140778 |
Donald G. York | 160 | 681 | 156579 |
Takeo Kanade | 147 | 799 | 103237 |
Gillian R. Knapp | 145 | 460 | 121477 |
Olaf Reimer | 144 | 716 | 74359 |
R. A. Sunyaev | 141 | 848 | 107966 |
Christopher T. Russell | 137 | 2378 | 97268 |
Hui Li | 135 | 2982 | 105903 |
Neil Gehrels | 134 | 727 | 80804 |
Christopher B. Field | 133 | 408 | 88930 |
Igor V. Moskalenko | 132 | 542 | 58182 |
William T. Reach | 131 | 535 | 90496 |
Adam Burrows | 130 | 623 | 55483 |