Institution
University of Saint Mary
Education•Leavenworth, Kansas, United States•
About: University of Saint Mary is a education organization based out in Leavenworth, Kansas, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 2276 authors who have published 2399 publications receiving 58990 citations. The organization is also known as: University of St. Mary & University of St Mary.
Topics: Population, Galaxy, Active galactic nucleus, Cancer, Health care
Papers published on a yearly basis
Papers
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TL;DR: The thesis of this paper is that the business model plays the primary role in the development of a e-commerce benchmark, the business that determines processes and transactions and thus also the database and navigational designs.
82 citations
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TL;DR: In this article, the authors report on the results of spectral fits made to data obtained from a 168 ks Suzaku observation of the Seyfert 1 galaxy Fairall 9.
Abstract: We report on the results of spectral fits made to data obtained from a 168 ks Suzaku observation of the Seyfert 1 galaxy Fairall 9. The source is clearly detected out to 30 keV. The observed spectrum is fairly simple; it is well described by a power law with soft excess and disk reflection. A broad iron line is detected, and easily separated from distinct narrow components owing to the resolution of the CCDs in the X-ray Imaging Spectrometer (XIS). The broad line is revealed to be asymmetric, consistent with a disk origin. We fit the XIS and Hard X-ray Detector spectra with relativistically blurred disk reflection models. With the assumption that the inner disk extends to the innermost stable circular orbit, the best-fit model implies a black hole spin parameter of a = 0.60 ± 0.07 and excludes extremal values at a high level of confidence. We discuss this result in the context of Seyfert observations and models of the cosmic distribution of black hole spin.
81 citations
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University of Cambridge1, European Space Agency2, Wayne State University3, University of Saint Mary4, California Institute of Technology5, Montana State University6, Polish Academy of Sciences7, University of Maryland, College Park8, University of Michigan9, Spanish National Research Council10, Stanford University11
TL;DR: In this paper, a detailed spectral analysis of the recent 1.5m XMM-Newton observing campaign on the narrow-line Seyfert 1 galaxy IRAS 13224−3809 is presented.
Abstract: We present a detailed spectral analysis of the recent 1.5 Ms XMM–Newton observing campaign on the narrow-line Seyfert 1 galaxy IRAS 13224−3809, taken simultaneously with 500 ks of NuSTAR data. The X-ray light curve shows three flux peaks, registering at about 100 times the minimum flux seen during the campaign, and rapid variability with a time-scale of kiloseconds. The spectra are well fit with a primary power-law continuum, two relativistic-blurred reflection components from the inner accretion disc with very high iron abundance, and a simple blackbody-shaped model for the remaining soft excess. The spectral variability is dominated by the power-law continuum from a corona region within a few gravitational radii from the black hole. Additionally, blueshifted Ne X, Mg XII, Si XIV, and S XVI absorption lines are identified in the stacked low-flux spectrum, confirming the presence of a highly ionized outflow with velocity up to v = 0.267 and 0.225 c. We fit the absorption features with xstar models and find a relatively constant velocity outflow through the whole observation. Finally, we replace the bbody and supersolar abundance reflection models by fitting the soft excess successfully with the extended reflection model relxillD, which allows for higher densities than the standard relxill model. This returns a disc electron density n_e > 10^(18.7) cm^(−3) and lowers the iron abundance from Z_(Fe) = 24^(+3)_(−4)Z_⊙ with n-e = 10^(15) cm^(-3) to Z_(Fe) = 6.6^(+0.8)_(-2.1)Z_⊙.
81 citations
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TL;DR: The goal was to profile resident participation in surgical skills simulation, recognize potential barriers to voluntary simulator use, and identify simulation tools and tasks preferred by residents to improve participation in simulation training.
80 citations
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TL;DR: In this article, the authors identify a significant selection effect operating on the Cosmic X-ray Background (CXB) and flux-limited AGN surveys, and outline how they must depend heavily on the spin distribution of black holes.
Abstract: The Cosmic X-ray Background (CXB) is the total emission from past accretion activity onto supermassive black holes in active galactic nuclei (AGN) and peaks in the hard X-ray band (30 keV). In this paper, we identify a significant selection effect operating on the CXB and flux-limited AGN surveys, and outline how they must depend heavily on the spin distribution of black holes. We show that, due to the higher radiative efficiency of rapidly-spinning black holes, they will be over-represented in the X-ray background, and therefore could be a dominant contributor to the CXB. Using a simple bimodal spin distribution, we demonstrate that only 15 per cent maximally-spinning AGN can produce 50 per cent of the CXB. We also illustrate that invoking a small population of maximally-spinning black holes in CXB synthesis models can reproduce the CXB peak without requiring large numbers of Compton-thick AGN. The spin bias is even more pronounced for flux-limited surveys: 7 per cent of sources with maximally-spinning black holes can produce half of the source counts. The detectability for maximum spin black holes can be further boosted in hard (>10 keV) X-rays by up to ~60 per cent due to pronounced ionised reflection, reducing the percentage of maximally spinning black holes required to produce half of the CXB or survey number counts further. A host of observations are consistent with an over-representation of high-spin black holes. Future NuSTAR and ASTRO-H hard X-ray surveys will provide the best constraints on the role of spin within the AGN population.
80 citations
Authors
Showing all 2277 results
Name | H-index | Papers | Citations |
---|---|---|---|
David R. Holmes | 161 | 1624 | 114187 |
Jeremy K. Nicholson | 141 | 773 | 80275 |
Shaun Purcell | 120 | 326 | 132973 |
Brad K. Gibson | 94 | 564 | 38959 |
Andrew N. Nicolaides | 90 | 572 | 30861 |
Mark D. Fleming | 81 | 433 | 36107 |
Jill Clayton-Smith | 74 | 308 | 19168 |
Alejandro A. Rabinstein | 72 | 725 | 33802 |
Philip B. Gorelick | 70 | 297 | 26424 |
Lucien C. Manchester | 67 | 113 | 18924 |
Elizabeth Murphy | 66 | 259 | 16966 |
Graeme C.M. Black | 64 | 274 | 15554 |
Raul Urrutia | 60 | 293 | 11664 |
Jane McCusker | 59 | 220 | 11538 |
Christopher J. Mathias | 58 | 278 | 16171 |