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Predicting The Starquakes In Psr J0537–6910
No full textThis is the pre-published version harvested from ArXiv. The published version is located at http://iopscience.iop.org/0004-637X/652/2/1531/We report on more than 7 yr of monitoring of PSR J0537-6910, the 16 ms pulsar in the LMC, using data acquired with RXTE. During this campaign the pulsar experienced 23 sudden increases in frequency ("glitches") amounting to a total gain of over 6 ppm of rotation frequency superposed on its gradual spin-down of = -2 × 10-10 Hz s-1. The time interval from one glitch to the next obeys a strong linear correlation to the amplitude of the first glitch, with a mean slope of about 400 days ppm-1 (6.5 days μHz-1), such that these intervals can be predicted to within a few days, an accuracy that has never before been seen in any other pulsar. There appears to be an upper limit of ~40 μHz for the size of glitches in all pulsars, with the 1999 April glitch of PSR J0537-6910 the largest so far. The change of its spin-down across the glitches, Δ, appears to have the same hard lower limit, -1.5 × 10-13 Hz s-1, as that observed in all other pulsars. The spin-down continues to increase in the long term, = -10-21 Hz s-2, and thus the timing age of PSR J0537-6910 (-0.5ν-1) continues to decrease at a rate of nearly 1 yr every year, consistent with movement of its magnetic moment away from its rotational axis by 1 rad every 10,000 yr, or about 1 m yr-1. PSR J0537-6910 was likely to have been born as a nearly aligned rotator spinning at 75-80 Hz, with a || considerably smaller than its current value of 2 × 10-10 Hz s-1. Its pulse profile consists of a single pulse that is found to be flat at its peak for at least 0.02 cycles.153
Variability survey in NGC 6910, the open cluster rich in β Cephei-type stars
Get PDFNGC 6910 is the northern hemisphere open cluster known to be rich in β Cephei-type stars. Using four-season photometry obtained in Białków (Poland) and Xinglong (China) observatories, we performed variability survey of NGC 6910. As the result, we found over 100 variable stars in the field of the cluster, including many stars showing variability due to pulsations and binarity. Thanks to the spectroscopic observations, we also detected changes in the profiles of spectral lines of β Cep stars, caused by pulsation
General Lee and Confederate Army Action
No full textThe the 8MM reel contains approximately 45-50 feet of footage. The reel is enclosed in an orange-yellow cardboard box. The film\u27s title appears at the box\u27s bottom. Reel is one of two reels in set (6910 and 6911).https://scholarsjunction.msstate.edu/fvw-audio-visual/1001/thumbnail.jp
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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Constraints from LIGO O3 Data on Gravitational-wave Emission Due to R-modes in the Glitching Pulsar PSR J0537-6910
No full textWe present a search for continuous gravitational-wave emission due to r-modes in the pulsar PSR J0537-6910 using data from the LIGO-Virgo Collaboration observing run O3. PSR J0537-6910 is a young energetic X-ray pulsar and is the most frequent glitcher known. The inter-glitch braking index of the pulsar suggests that gravitational-wave emission due to r-mode oscillations may play an important role in the spin evolution of this pulsar. Theoretical models confirm this possibility and predict emission at a level that can be probed by ground-based detectors. In order to explore this scenario, we search for r-mode emission in the epochs between glitches by using a contemporaneous timing ephemeris obtained from NICER data. We do not detect any signals in the theoretically expected band of 86-97 Hz, and report upper limits on the amplitude of the gravitational waves. Our results improve on previous amplitude upper limits from r-modes in J0537-6910 by a factor of up to 3 and place stringent constraints on theoretical models for r-mode-driven spin-down in PSR J0537-6910, especially for higher frequencies at which our results reach below the spin-down limit defined by energy conservation. © 2021. The American Astronomical Society. All rights reserved..Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Constraints from LIGO O3 Data on Gravitational-wave Emission Due to R-modes in the Glitching Pulsar PSR J0537-6910
No full textWe present a search for continuous gravitational-wave emission due to r-modes in the pulsar PSR J0537-6910 using data from the LIGO-Virgo Collaboration observing run O3. PSR J0537-6910 is a young energetic X-ray pulsar and is the most frequent glitcher known. The inter-glitch braking index of the pulsar suggests that gravitational-wave emission due to r-mode oscillations may play an important role in the spin evolution of this pulsar. Theoretical models confirm this possibility and predict emission at a level that can be probed by ground-based detectors. In order to explore this scenario, we search for r-mode emission in the epochs between glitches by using a contemporaneous timing ephemeris obtained from NICER data. We do not detect any signals in the theoretically expected band of 86-97 Hz, and report upper limits on the amplitude of the gravitational waves. Our results improve on previous amplitude upper limits from r-modes in J0537-6910 by a factor of up to 3 and place stringent constraints on theoretical models for r-mode-driven spin-down in PSR J0537-6910, especially for higher frequencies at which our results reach below the spin-down limit defined by energy conservation.</p
Constraints from LIGO O3 data on gravitational-wave emission due to r-modes in the glitching pulsar PSR J0537-6910
Get PDFWe present a search for continuous gravitational-wave emission due to r-modes in the pulsar PSR J0537-6910 using data from the LIGO-Virgo Collaboration observing run O3. PSR J0537-6910 is a young energetic X-ray pulsar and is the most frequent glitcher known. The inter-glitch braking index of the pulsar suggests that gravitational-wave emission due to r-mode oscillations may play an important role in the spin evolution of this pulsar. Theoretical models confirm this possibility and predict emission at a level that can be probed by ground-based detectors. In order to explore this scenario, we search for r-mode emission in the epochs between glitches by using a contemporaneous timing ephemeris obtained from NICER data. We do not detect any signals in the theoretically expected band of 86-97 Hz, and report upper limits on the amplitude of the gravitational waves. Our results improve on previous amplitude upper limits from r-modes in J0537-6910 by a factor of up to 3 and place stringent constraints on theoretical models for r-mode driven spin-down in PSR J0537-6910, especially for higher frequencies at which our results reach below the spin-down limit defined by energy conservation
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