Institution
Jet Propulsion Laboratory
Facility•La Cañada Flintridge, California, United States•
About: Jet Propulsion Laboratory is a facility organization based out in La Cañada Flintridge, California, United States. It is known for research contribution in the topics: Mars Exploration Program & Telescope. The organization has 8801 authors who have published 14333 publications receiving 548163 citations. The organization is also known as: JPL & NASA JPL.
Topics: Mars Exploration Program, Telescope, Galaxy, Coronagraph, Planet
Papers published on a yearly basis
Papers
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University of Kent1, Baylor University2, Rutherford Appleton Laboratory3, European Space Research and Technology Centre4, Max Planck Society5, Jet Propulsion Laboratory6, University of Sheffield7, Technische Universität München8, Lund University9, Community emergency response team10, Cardiff University11
TL;DR: Data at large masses recently analysed from the DIDSY data set show clear evidence of a decrease in the mass distribution index at these masses within the coma, and it is shown that such a value of the mass index can provide sufficient mass for consistency with the observed deceleration.
Abstract: Analysis of the data from Giotto’s Dust Impact Detection System experiment (DIDSY) is presented These data represent measurement of the size of dust grains incident on the Giotto dust shield along its trajectory through the coma of comet P/Halley on 1986 March 13/14 First detection occurred at some 287000 km distance from the nucleus on the inbound leg; the majority of the DIDSY subsystems remained operational after closest approach (604 km) yielding the last detection at about 202000 km from the nucleus
150 citations
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TL;DR: The Global Space-based Stratospheric Aerosol and Gas Experiment (SAGE) series of instruments was used to provide the input data to the construction of the GloSSAC stratospheric aerosol forcing data set.
Abstract: . We describe the construction of a continuous 38-year record of stratospheric
aerosol optical properties. The Global Space-based Stratospheric Aerosol
Climatology, or GloSSAC, provided the input data to the construction of the
Climate Model Intercomparison Project stratospheric aerosol forcing data set
(1979–2014) and we have extended it through 2016 following an identical
process. GloSSAC focuses on the Stratospheric Aerosol and Gas Experiment
(SAGE) series of instruments through mid-2005, and on the Optical
Spectrograph and InfraRed Imager System (OSIRIS) and the Cloud-Aerosol Lidar
and Infrared Pathfinder Satellite Observation (CALIPSO) data thereafter. We
also use data from other space instruments and from ground-based, air, and
balloon borne instruments to fill in key gaps in the data set. The end result
is a global and gap-free data set focused on aerosol extinction coefficient
at 525 and 1020 nm and other parameters on an “as available” basis. For
the primary data sets, we developed a new method for filling the
post-Pinatubo eruption data gap for 1991–1993 based on data from the
Cryogenic Limb Array Etalon Spectrometer. In addition, we developed a new
method for populating wintertime high latitudes during the SAGE period
employing a latitude-equivalent latitude conversion process that greatly
improves the depiction of aerosol at high latitudes compared to earlier
similar efforts. We report data in the troposphere only when and where it is
available. This is primarily during the SAGE II period except for the most
enhanced part of the Pinatubo period. It is likely that the upper troposphere
during Pinatubo was greatly enhanced over non-volcanic periods and that
domain remains substantially under-characterized. We note that aerosol levels
during the OSIRIS/CALIPSO period in the lower stratosphere at mid- and high
latitudes is routinely higher than what we observed during the SAGE II
period. While this period had nearly continuous low-level volcanic activity,
it is possible that the enhancement in part reflects deficiencies in the data
set. We also expended substantial effort to quality assess the data set and
the product is by far the best we have produced. GloSSAC version 1.0 is
available in netCDF format at the NASA Atmospheric Data Center at
https://eosweb.larc.nasa.gov/ . GloSSAC users should cite this paper and
the data set DOI ( https://doi.org/10.5067/GloSSAC-L3-V1.0 ).
150 citations
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TL;DR: The concept of primordial rubble piles as discussed by the authors was proposed as a modification of the basic Whipple model, not as a replacement for it, and is analogous to the "rubble pile" model suggested for the larger main-belt asteroids, although the larger cometary fragments are expected to be primordial condensations rather than collisionally derived debris.
Abstract: Whipple's icy conglomerate model for the cometary nucleus has had considerable sucess in explaining a variety of cometary phenomena such as gas production rates and nongravitational forces. However, as discussed here, both observational evidence and theoretical considerations suggest that the cometary nucleus may not be a well-consolidated single body, but may instead be a loosely bound agglomeration of smaller fragments, weakly bonded and subject to occasional or even frequent disruptive events. The proposed model is analogous to the 'rubble pile' model suggested for the larger main-belt asteroids, although the larger cometary fragments are expected to be primordial condensations rather than collisionally derived debris as in the asteroid case. The concept of cometary nuclei as primordial rubble piles is proposed as a modification of the basic Whipple model, not as a replacement for it.
150 citations
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Jet Propulsion Laboratory1, California Institute of Technology2, University of California, Irvine3, Los Alamos National Laboratory4, University of Tokyo5, Japan Aerospace Exploration Agency6, Seoul National University7, University of California, Los Angeles8, Korea Astronomy and Space Science Institute9, Academia Sinica10, Tohoku University11
TL;DR: New EBL anisotropy measurements from a specialized sounding rocket experiment at 1.1 and 1.6 micrometers are reported, associated with an EBL intensity that is comparable to the background from known galaxies measured through number counts and therefore a substantial contribution to the energy contained in photons in the cosmos.
Abstract: Extragalactic background light (EBL) anisotropy traces variations in the total production of photons over cosmic history and may contain faint, extended components missed in galaxy point-source surveys. Infrared EBL fluctuations have been attributed to primordial galaxies and black holes at the epoch of reionization (EOR) or, alternately, intrahalo light (IHL) from stars tidally stripped from their parent galaxies at low redshift. We report new EBL anisotropy measurements from a specialized sounding rocket experiment at 1.1 and 1.6 micrometers. The observed fluctuations exceed the amplitude from known galaxy populations, are inconsistent with EOR galaxies and black holes, and are largely explained by IHL emission. The measured fluctuations are associated with an EBL intensity that is comparable to the background from known galaxies measured through number counts and therefore a substantial contribution to the energy contained in photons in the cosmos.
150 citations
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TL;DR: In this article, a 0.5-m right-hand circularly polarized planar reflectarray antenna is designed using microstrip ring elements of variable rotations to achieve a cophasal beam at broadside.
Abstract: This paper reports a dual frequency dual layer circularly polarized reflectarray operating in the C and Ka bands. A 0.5-m right-hand circularly polarized planar reflectarray antenna is designed using microstrip ring elements of variable rotations to achieve a cophasal beam at broadside. The microstrip ring elements are more compact than the traditional reflectarray elements and can minimize blockage for the multilayer multifrequency applications. The highest efficiencies measured are 46% at 7.3 GHz and 38% at 31.75 GHz. The tested cross-polarization levels are -21 dB at 7.3 GHz and -29.2 dB at 31.75 GHz at the broadside direction. The tested results show that the designed ring element is suitable for both the single and dual layer applications with good bandwidth and circularly polarized performance.
150 citations
Authors
Showing all 9033 results
Name | H-index | Papers | Citations |
---|---|---|---|
B. P. Crill | 148 | 486 | 111895 |
George Helou | 144 | 662 | 96338 |
H. K. Eriksen | 141 | 474 | 104208 |
Charles R. Lawrence | 141 | 528 | 104948 |
W. C. Jones | 140 | 395 | 97629 |
Gianluca Morgante | 138 | 478 | 98223 |
Jean-Paul Kneib | 138 | 805 | 89287 |
Kevin M. Huffenberger | 138 | 402 | 93452 |
Robert H. Brown | 136 | 1174 | 79247 |
Federico Capasso | 134 | 1189 | 76957 |
Krzysztof M. Gorski | 132 | 380 | 105912 |
Olivier Doré | 130 | 427 | 104737 |
Mark E. Thompson | 128 | 527 | 77399 |
Clive Dickinson | 123 | 501 | 80701 |
Daniel Stern | 121 | 788 | 69283 |