1,723,351 research outputs found
THE ORBITAL PERIOD OF SWIFT J1626.6-5156
No full textWe present the discovery of the orbital period of Swift J1626.6-5156. Since its discovery in 2005, the source has been monitored with Rossi X-Ray Timing Explorer, especially during the early stage of the outburst and into the X-ray modulating episode. Using a data span of similar to 700 days, we obtain the orbital period of the system as 132.9 days. We find that the orbit is close to a circular shape with an eccentricity 0.08, that is one of the smallest among Be/X-ray binary systems. Moreover, we find that the timescale of the X-ray modulations varied, which led to earlier suggestions of orbital periods at about a third and half of the orbital period of Swift J1626.6-5156
Pulse Profiles of Swift J1626.6+5156
No full textIn this paper, we analyzed pulse profiles of Swift J1626.6+5156 using the lightcurves from RXTE‐PCA observations between MJD 53724 (just after the outburst) and MJD 55113 and a Chandra‐ACIS dataset on MJD 54897 with a 20 ks exposure. We found that pulse profiles show morphological variations and pulsations do not cease even ∼1200 days after the outburst. Despite these variations, we did not find any significant variation in the pulsed fraction with decreasing X‐ray flux
Bright flares from the X-ray pulsar SWIFT J1626.6–5156
No full textAims. We have performed a timing and spectral analysis of the X-ray pulsar SWIFT J1626.6–5156 during
a major X-ray outburst in order to unveil its nature and investigate
its flaring activity.
Methods. Epoch- and pulse-folding techniques were used to derive the spin period.
Time-average and pulse-phase spectroscopy were employed to study the
spectral variability in the flare and out-of-flare states and energy
variations with pulse phase. Power spectra were obtained to investigate the
periodic and aperiodic variability.
Results. Two large flares, with a duration of ~450 s were observed on 24
and 25 December 2005. During the flares, the X-ray intensity increased by a
factor of 3.5, while the peak-to-peak pulsed amplitude increased from 45%
to 70%. A third, smaller flare
of duration ~180 s was observed on 27 December 2005. The flares seen in
SWIFT J1626.6–5156 constitute the shortest events of this kind ever reported in a
high-mass X-ray binary. In addition to the flaring activity, strong X-ray
pulsations with s characterise the X-ray
emission in SWIFT J1626.6–5156. After the major outburst, the light curve exhibits
strong long-term variations modulated with a 45-day period. We relate this
modulation to the orbital period of the system or to a harmonic.
Power density spectra show, in addition to the harmonic components of the
pulsation, strong band-limited noise with an integrated 0.01-100 Hz
fractional rms of around 40% that increased to 64% during the flares. A
weak QPO (fractional rms 4.7%) with characteristic frequency of 1 Hz was
detected in the non-flare emission.
Conclusions. The timing (short X-ray pulsations, long orbital period) and spectral (power-law with cut off energy
and neutral iron line) properties of SWIFT J1626.6–5156 are characteristic of Be/X-ray
binaries
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
5156. Krause (G.), Beziehungen zwischen Habsburg und Burgund bis zum Ausgang der Trier Zusammenkunft, Graudenz, 1876
No full text5156. Krause (G.), Beziehungen zwischen Habsburg und Burgund bis zum Ausgang der Trier Zusammenkunft, Graudenz, 1876. In: Molinier Auguste. Les Sources de l'histoire de France - Des origines aux guerres d'Italie (1494). V. Introduction générale - Les Valois (suite), Louis XI et Charles VIII (1461-1494) Paris : A. Picard et fils, 1904. p. 111
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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