Institution
Raytheon
Company•Waltham, Massachusetts, United States•
About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.
Topics: Signal, Antenna (radio), Radar, Turbine, Amplifier
Papers published on a yearly basis
Papers
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TL;DR: In this paper, the authors evaluated whether there is a signal in the normalized difference snow index (NDSI) that can be used to estimate the fraction of snow within a 500 m MODIS pixel and thereby enhance the use of NDSI approach in monitoring snow cover.
550 citations
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TL;DR: The Hyperion Imaging Spectrometer was the first imaging spectrometer to routinely acquire science-grade data from Earth orbit and met or exceeded predictions including continued operation well beyond the planned one-year program.
Abstract: The Hyperion Imaging Spectrometer was the first imaging spectrometer to routinely acquire science-grade data from Earth orbit. Instrument performance was validated and carefully monitored through a combination of calibration approaches: solar, lunar, earth (vicarious) and atmospheric observations complemented by onboard calibration lamps and extensive prelaunch calibration. Innovative techniques for spectral calibration of space-based sensors were also tested and validated. Instrument performance met or exceeded predictions including continued operation well beyond the planned one-year program.
549 citations
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TL;DR: In this paper, expressions for the conductor loss in microstrip transmission lines are derived for rutile and alumina substrates, taking into account the finite thickness of the strip conductor and apply to the mixed dielectric system.
Abstract: Expressions are derived for the conductor loss in microstrip transmission lines. The formulas take into account the finite thickness of the strip conductor and apply to the mixed dielectric system. Good agreement with experimental data is obtained for rutile and alumina substrates.
543 citations
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TL;DR: In this article, the photometric errors of the external calibrator for the Far Infrared Absolute Spectrophotometer (FIRAS) instrument on the COBE are smaller than the measurement errors on the CMBR spectrum (typically 0.02 MJy sr-1, 1 σ).
Abstract: The photometric errors of the external calibrator for the Far Infrared Absolute Spectrophotometer (FIRAS) instrument on the COBE are smaller than the measurement errors on the cosmic microwave background radiation (CMBR) spectrum (typically 0.02 MJy sr-1, 1 σ) and smaller than 0.01% of the peak brightness of the CMB. The calibrator is a reentrant cone, shaped like a trumpet mute, made of Eccosorb iron-loaded epoxy. It fills the entire beam of the instrument and is the source of its accuracy. Its known errors are caused by reflections, temperature gradients, and leakage through the material and around the edge. Estimates and limits are given for all known error sources. Improvements in understanding the temperature measurements of the calibrator allow an improved CMB temperature determination of 2.725±0.002 K.
542 citations
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Max Planck Society1, National Radio Astronomy Observatory2, University of Maryland, College Park3, University of Toledo4, Ohio State University5, Princeton University6, McMaster University7, University of Massachusetts Amherst8, University of Cambridge9, University of Paris-Sud10, Stony Brook University11, Heidelberg University12, University of Hertfordshire13, ASTRON14, University of Wyoming15, University of Arizona16, Raytheon17, INAF18, Institut d'Astrophysique de Paris19, University of California, San Diego20, California Institute of Technology21, Leiden University22, Space Telescope Science Institute23, Louisiana State University24, DSM25, University of Cologne26
TL;DR: In this paper, the authors presented a large-scale spatial resolution map of the CO-to-H$2}$ conversion factor and dust-togas ratio (DGR) in 26 nearby, star-forming galaxies.
Abstract: We present ~{}kiloparsec spatial resolution maps of the CO-to-H$_{2}$ conversion factor ({$α$}$_{CO}$) and dust-to-gas ratio (DGR) in 26 nearby, star-forming galaxies. We have simultaneously solved for {$α$}$_{CO}$ and the DGR by assuming that the DGR is approximately constant on kiloparsec scales. With this assumption, we can combine maps of dust mass surface density, CO-integrated intensity, and H I column density to solve for both {$α$}$_{CO}$ and the DGR with no assumptions about their value or dependence on metallicity or other parameters. Such a study has just become possible with the availability of high-resolution far-IR maps from the Herschel key program KINGFISH, $^{12}$CO J = (2-1) maps from the IRAM 30 m large program HERACLES, and H I 21 cm line maps from THINGS. We use a fixed ratio between the (2-1) and (1-0) lines to present our {$α$}$_{CO}$ results on the more typically used $^{12}$CO J = (1-0) scale and show using literature measurements that variations in the line ratio do not affect our results. In total, we derive 782 individual solutions for {$α$}$_{CO}$ and the DGR. On average, {$α$}$_{CO}$ = 3.1 M $_{☉}$ pc$^{–2}$ (K km s$^{–1}$)$^{–1}$ for our sample with a standard deviation of 0.3 dex. Within galaxies, we observe a generally flat profile of {$α$}$_{CO}$ as a function of galactocentric radius. However, most galaxies exhibit a lower {$α$}$_{CO}$ value in the central kiloparsec{mdash}a factor of ~{}2 below the galaxy mean, on average. In some cases, the central {$α$}$_{CO}$ value can be factors of 5-10 below the standard Milky Way (MW) value of {$α$}$_{CO, MW}$ = 4.4 M $_{☉}$ pc$^{–2}$ (K km s$^{–1}$)$^{–1}$. While for {$α$}$_{CO}$ we find only weak correlations with metallicity, the DGR is well-correlated with metallicity, with an approximately linear slope. Finally, we present several recommendations for choosing an appropriate {$α$}$_{CO}$ for studies of nearby galaxies.
533 citations
Authors
Showing all 15293 results
Name | H-index | Papers | Citations |
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Peter J. Kahrilas | 109 | 586 | 46064 |
Edward J. Wollack | 104 | 732 | 102070 |
Duong Nguyen | 98 | 674 | 47332 |
Miroslav Krstic | 95 | 955 | 42886 |
Steven L. Suib | 89 | 862 | 34189 |
Gabriel M. Rebeiz | 87 | 806 | 32443 |
Charles W. Engelbracht | 83 | 210 | 28137 |
Paul A. Grayburn | 77 | 397 | 26880 |
Eric J. Huang | 72 | 201 | 22172 |
Thomas F. Eck | 72 | 150 | 32965 |
David M. Margolis | 70 | 227 | 17314 |
David W. T. Griffith | 65 | 288 | 14232 |
Gerhard Klimeck | 65 | 685 | 18447 |
Nickolay A. Krotkov | 63 | 219 | 11250 |
Olaf Stüve | 63 | 290 | 14268 |