Diphtheria. (Letter From Dr. T. Laycock.)

Laycock, Thomas

doi:10.1016/s0140-6736(02)42154-x

Cited by 3 publications

(5 citation statements)

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“…For matching with optical or IR sources, we use the P err along with other relevant information such as boresight offset, optical error circle, etc (Laycock et al 2005;Zhao et al 2005). For the X-ray data base, PXP generates an index table that cross-correlates potentially identical sources that appear in multiple observations of the same region.…”

Section: Positional Uncertainty and Cross-correlating X-ray Sourcesmentioning

confidence: 99%

“…Note Eq. (6) is used only for cross-correlating (or boresighting) X-ray to Xray observations; for matching with optical or IR sources, see (Laycock et al 2005;Zhao et al 2005).…”

Section: Positional Uncertainty and Cross-correlating X-ray Sourcesmentioning

confidence: 99%

“…The overview of the project is given in Grindlay et al (2005). The methodology and initial results of the optical and IR surveys are presented in Zhao et al (2005), Rogel et al (2005) and Laycock et al (2005), respectively.…”

Section: Introductionmentioning

confidence: 99%

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X‐Ray Processing of ChaMPlane Fields: Methods and Initial Results for Selected Anti–Galactic Center Fields

Hong

Berg

Schlegel

et al. 2005

ApJ

111

127

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We describe the X-ray analysis procedure of the on-going Chandra Multiwavelength Plane (ChaMPlane) survey and report the initial results from the analysis of 15 selected anti-Galactic center observations (90 • < l < 270 • ). We describe the X-ray analysis procedures for ChaMPlane using custom-developed analysis tools appropriate for Galactic sources but also of general use: optimum photometry in crowded fields using advanced techniques for overlapping sources, rigorous astrometry and 95% error circles for combining X-ray images or matching to optical/IR images, and application of quantile analysis for spectral analysis of faint sources. We apply these techniques to 15 anti-Galactic center observations (of 14 distinct fields) in which we have detected 921 X-ray point sources. We present logN-logS distributions and quantile analysis to show that in the hard band (2 -8 keV) active galactic nuclei dominate the sources. Complete analysis of all ChaMPlane anti-Galactic center fields will be given in a subsequent paper, followed by papers on sources in the Galactic center and Bulge regions.

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Section: Positional Uncertainty and Cross-correlating X-ray Sourcesmentioning

confidence: 99%

“…Note Eq. (6) is used only for cross-correlating (or boresighting) X-ray to Xray observations; for matching with optical or IR sources, see (Laycock et al 2005;Zhao et al 2005).…”

Section: Positional Uncertainty and Cross-correlating X-ray Sourcesmentioning

confidence: 99%

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X‐Ray Processing of ChaMPlane Fields: Methods and Initial Results for Selected Anti–Galactic Center Fields

Hong

Berg

Schlegel

et al. 2005

ApJ

111

127

View full text Add to dashboard Cite

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“…The masses of the WR stars in IC 10 X-1 and NGC 300 X-1 were derived from the optical brightness of these stars. The masses of their compact companions are very uncertain, as discussed by Laycock et al (2015) and Carpano and Soria (this volume). The reason is that these masses were derived from the observed radial velocity curves of the emission lines of the WR stars, which curves are almost 90 degrees out of phase with the radial velocity curves expected from the X-ray light curves of these binaries.…”

Section: From Black-hole Hmxbs To Wrxbs and Double Black Holesmentioning

confidence: 96%

High-Mass X-ray Binaries: progenitors of double compact objects

Heuvel

2018

Proc. IAU

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A summary is given of the present state of our knowledge of High-Mass X-ray Binaries (HMXBs), their formation and expected future evolution. Among the HMXB-systems that contain neutron stars, only those that have orbital periods upwards of one year will survive the Common-Envelope (CE) evolution that follows the HMXB phase. These systems may produce close double neutron stars with eccentric orbits. The HMXBs that contain black holes do not necessarily evolve into a CE phase. Systems with relatively short orbital periods will evolve by stable Roche-lobe overflow to short-period Wolf-Rayet (WR) X-ray binaries containing a black hole. Two other ways for the formation of WR X-ray binaries with black holes are identified: CE-evolution of wide HMXBs and homogeneous evolution of very close systems. In all three cases, the final product of the WR X-ray binary will be a double black hole or a black hole neutron star binary. 2Edward P.J. van den Heuvel evolve into WRXBs, and on possible other channels for the formation of WRXBs. In HMXBs with short orbital periods that contain a black hole, stable Roche-lobe overflow is possible, such that CEE can be avoided, and the systems may survive as close binaries consisting of a helium star (WR star) and a black hole. It is argued that the compact stars in practically all WRXBs must be black holes, making these systems ideal progenitor systems of double black holes and Black hole-Neutron star (BH-NS) binaries. The different types of High-Mass X-ray BinariesThere are three main types of HMXBs, with the following characteristics: (i) The first type, discovered by Schreier et al. (1972) and Webster & Murdin (1972), is that of the supergiant HMXBs. In these systems the donor star is an O-or early Btype supergiant star that is close to filling its Roche lobe. The orbital periods of these systems, many of which are eclipsing, are mostly shorter than 15 days. These systems are persistent (permanent) X-ray sources, mostly powered by the capture of matter from the strong stellar wind of the supergiant companion. In a few cases, such as the 2.1 d orbit eclipsing and regularly pulsating X-ray source Centaurus X-3 , the X-ray source is powered by beginning Roche-lobe overflow. The supergiant HMXBs are relatively rare, their total known number in the Galaxy being about 30, and, in practically all of them, the compact star is a neutron star: a X-ray pulsar. The blue supergiants have masses typically in the range 20 to 50M .(ii) The second type of systems, practically all containing neutron stars, is that of the B-emission X-ray Binaries (short: BeXBs), discovered in 1975 with the Ariel V satellite, and first recognized and explained as a separate class by Maraschi et al. (1976). Most of these systems are recurrent transients, which can be quiet for many decades and then suddenly flare up as a strong pulsating X-ray source for weeks to months. The companion stars here are rapidly rotating B-stars that are in or very close to the main sequence and are deep inside their Roche lobes; they have a va...

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“…Numerous local variations in procedure no doubt exist, but Laycock (1950), quoting Ploss and Bartles, distinguishes two main types of procedure-excision and infibulation. Excision may be confined to the clitoris or extended to parts of the labia minora as well.…”

Section: Commentmentioning

confidence: 99%