Institution
Smithsonian Astrophysical Observatory
Facility•Cambridge, Massachusetts, United States•
About: Smithsonian Astrophysical Observatory is a facility organization based out in Cambridge, Massachusetts, United States. It is known for research contribution in the topics: Galaxy & Stars. The organization has 1665 authors who have published 3622 publications receiving 132183 citations. The organization is also known as: SAO.
Topics: Galaxy, Stars, Telescope, Luminosity, Star formation
Papers published on a yearly basis
Papers
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TL;DR: In this article, a large area, fully sampled maps of the Carina molecular cloud complex in the CO (J = 4→3) and neutral carbon [C I] 3P1 → 3P0 transitions were obtained using the 1.7 m Antarctic Submillimeter Telescope and Remote Observatory (AST/RO).
Abstract: We present large-area, fully sampled maps of the Carina molecular cloud complex in the CO (J = 4→3) and neutral carbon [C I] 3P1 → 3P0 transitions. These data were obtained using the 1.7 m Antarctic Submillimeter Telescope and Remote Observatory (AST/RO). The maps cover an area of approximately 3 deg2 with a uniform 1' spatial sampling. Analysis of these data, in conjunction with CO (J = 1→0) data from the Columbia CO survey and the IRAS HIRES continuum maps for the same region, suggests that the spiral density wave shock associated with the Carina spiral arm may be playing an important role in the formation and dissociation of the cloud complex, as well as in maintaining the internal energy balance of the clouds in this region. Massive stars form at the densest regions of the molecular cloud complex. The winds and outflows associated with these stars have a disrupting effect on the complex and inject mechanical energy into the parent clouds, while the UV radiation from the young stars also heats the parent clouds. The present set of data suggests, however, that massive stars alone may not account for the energetics of the clouds in the Carina region. The details of the data and the correlation among the various data sets hint at the possible role that the spiral density wave shock plays in feeding interstellar turbulence and heating molecular clouds.
59 citations
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Ohio University1, INAF2, Columbia University3, University of Turku4, Purdue University5, Rice University6, University of Michigan7, Pulkovo Observatory8, Physical Research Laboratory9, Western Kentucky University10, National Autonomous University of Mexico11, University of Perugia12, Guangzhou University13, Isaac Newton Institute14, Saint Petersburg State University15, Smithsonian Astrophysical Observatory16, Academy of Sciences of Uzbekistan17, Astro Space Center18, National Radio Astronomy Observatory19, Helsinki University of Technology20, Osaka Kyoiku University21, University of Crete22, Foundation for Research & Technology – Hellas23, University of Missouri24, Japan Aerospace Exploration Agency25, Korea Astronomy and Space Science Institute26, Chinese Academy of Sciences27
TL;DR: The BL Lac object 3C 66A was the target of an extensive multi-wavelength monitoring campaign from 2003 July through 2004 April (with a core campaign occurring from 2003 September to 2003 December) involving observations throughout the electromagnetic spectrum.
Abstract: The BL Lac object 3C 66A was the target of an extensive multiwavelength monitoring campaign from 2003 July through 2004 April (with a core campaign from 2003 September to 2003 December) involving observations throughout the electromagnetic spectrum. Radio, infrared, and optical observations were carried out by the WEBT-ENIGMA collaboration. At higher energies, 3C 66A was observed in X-rays (RXTE), and at very high energy (VHE) in γ-rays (STACEE, VERITAS). In addition, the source has been observed with the VLBA at nine epochs throughout the period 2003 September to 2004 December, including three epochs contemporaneous with the core campaign. A gradual brightening of the source over the course of the campaign was observed at all optical frequencies, culminating in a very bright maximum around 2004 February 18. The WEBT campaign revealed microvariability with flux changes of ~5% on timescales as short as ~2 hr. The source was in a relatively bright state, with several bright flares on timescales of several days. The spectral energy distribution (SED) indicates a νFν peak in the optical regime. A weak trend of optical spectral hysteresis with a trend of spectral softening throughout both the rising and decaying phases has been found. On longer timescales, there appears to be a weak indication of a positive hardness-intensity correlation for low optical fluxes, which does not persist at higher flux levels. The 3-10 keV X-ray flux of 3C 66A during the core campaign was historically high and its spectrum very soft, indicating that the low-frequency component of the broadband SED extends beyond ~10 keV. No significant X-ray flux and/or spectral variability was detected. STACEE and Whipple observations provided upper flux limits at >150 and >390 GeV, respectively. The 22 and 43 GHz data from the three VLBA epochs made between 2003 September and 2004 January indicate a rather smooth jet with only very moderate internal structure. Evidence for superluminal motion (8.5 ± 5.6 h-1 c) was found in only one of six components, while the apparent velocities of all other components are consistent with 0. The radial radio brightness profile suggests a magnetic field decay ∝r-1 and, thus, a predominantly perpendicular magnetic field orientation.
59 citations
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TL;DR: The proposed measures of research impact, tori and riq, have been implemented in the Smithsonian/NASA Astrophysics Data System and it is demonstrated that these measures are substantially less vulnerable to temporal debasement and cross-disciplinary bias than the most popular current measures.
Abstract: Authorship and citation practices evolve with time and differ by academic discipline. As such, indicators of research productivity based on citation records are naturally subject to historical and disciplinary effects. We observe these effects on a corpus of astronomer career data constructed from a database of refereed publications. We employ a simple mechanism to measure research output using author and reference counts available in bibliographic databases to develop a citation-based indicator of research productivity. The total research impact (tori) quantifies, for an individual, the total amount of scholarly work that others have devoted to his/her work, measured in the volume of research papers. A derived measure, the research impact quotient (riq), is an age-independent measure of an individual's research ability. We demonstrate that these measures are substantially less vulnerable to temporal debasement and cross-disciplinary bias than the most popular current measures. The proposed measures of research impact, tori and riq, have been implemented in the Smithsonian/NASA Astrophysics Data System.
58 citations
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TL;DR: A Chandra X-ray observation has detected an unresolved source at the center of the supernova remnant Kes 79 as mentioned in this paper, which is similar to the central source in Cas A even though the Kes 79 remnant is considerably older.
Abstract: A Chandra X-ray observation has detected an unresolved source at the center of the supernova remnant Kes 79. The best single-model fit to the source spectrum is a blackbody with an X-ray luminosity of LX(0.3-8.0 keV) = 7 × 1033 ergs s-1. There is no evidence for a surrounding pulsar wind nebula. There are no cataloged counterparts at other wavelengths, but the absorption is high. The source properties are similar to the central source in Cas A even though the Kes 79 remnant is considerably older.
58 citations
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TL;DR: In this article, optical high-speed photometry of three millisecond pulsars with low-mass ( < 0.3 M) white dwarf companions was presented, bringing the total number of such systems with follow-up time-series photometry to five.
Abstract: We present optical high-speed photometry of three millisecond pulsars with low-mass ($< 0.3 M_{\odot}$) white dwarf companions, bringing the total number of such systems with follow-up time-series photometry to five. We confirm the detection of pulsations in one system, the white dwarf companion to PSR J1738+0333, and show that the pulsation frequencies and amplitudes are variable over many months. A full asteroseismic analysis for this star is under-constrained, but the mode periods we observe are consistent with expectations for a $M_{\star} = 0.16 - 0.19 M_{\odot}$ white dwarf, as suggested from spectroscopy. We also present the empirical boundaries of the instability strip for low-mass white dwarfs based on the full sample of white dwarfs, and discuss the distinction between pulsating low-mass white dwarfs and subdwarf A/F stars.
58 citations
Authors
Showing all 1666 results
Name | H-index | Papers | Citations |
---|---|---|---|
Lee Hartmann | 134 | 579 | 57649 |
David W. Latham | 127 | 852 | 67390 |
Chi Lin | 125 | 1313 | 102710 |
William R. Forman | 120 | 800 | 53717 |
Edo Berger | 118 | 578 | 47147 |
Joseph Silk | 108 | 1317 | 58146 |
Jon M. Miller | 107 | 706 | 50126 |
Fabrizio Fiore | 106 | 804 | 43260 |
Randall V. Martin | 105 | 396 | 57917 |
Christopher F. McKee | 103 | 368 | 44919 |
John P. Hughes | 101 | 616 | 36396 |
Wallace L. W. Sargent | 99 | 397 | 30265 |
Bryan Gaensler | 99 | 844 | 39851 |
Alexey Vikhlinin | 99 | 367 | 35822 |
Matthew J. Holman | 99 | 320 | 46577 |