On the Optical Search for the X-Ray Sources CYG X-1 and CYG X-2

Giacconi, R.; Gorenstein, P.; Gursky, H.; Usher, P. D.; Waters, J. R.; Sandage, A.; Osmer, Patrick S.; Peach, J. V.

doi:10.1086/180029

Cited by 49 publications

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“…The most noticeable effect was observed in Cyg X-3 by Gorenstein et al (1967) and the data are shown in Figure 8. We note that also sources The parameters Ea and T represent the best fit.…”

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confidence: 86%

“…The locations of the X-ray sources observed in this experiment as well as sources reported from a previous survey (Friedman et al, 1967) with their strength relative to the Crab (plus known supernova remnants) are shown. Gorenstein et al (1967), and Gursky et al (1967. I would like to restrict my remarks in this paper to aspects of those earlier publications which, together with the results of our most recent flight, have a bearing on (1) the X-ray emission from super nova remnants, and (2) the distribution of X-ray sources in the galaxy.…”

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confidence: 99%

“…This identical payload was flown, recovered, and reflown four times with only slight modifications. Details of the instrumentation have been described previously (Gursky et al, 1968;Gorenstein et al, 1969a, b). It consists of two large area banks of propor tional counters with slit type collimators and an aspect camera to obtain aspect by photography of the star field in visible light.…”

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confidence: 99%

“…(2) Galactic Distribution of X-Ray Sources As a result of previous surveys, we had adopted as a working hypothesis in a pre vious paper (Gursky et al, 1967) the point of view that X-ray sources were associated with the galactic spiral arm. Assuming all sources to be of the same intrinsic luminosity, it appeared possible to obtain a consistent picture by assuming that sources with /" between -15° to +17° lie in the Sagittarius arm and the ones with /" between + 36° to +80° corresponded to tangential directions of several arms.…”

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confidence: 99%

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Properties of individual X-ray sources: (Invited discourse)

Giacconi¹

1970

Symp. - Int. Astron. Union

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In the past 2 years the group at American Science & Engineering, Inc., including Gursky, Gorenstein, Kellogg and me, has been engaged in a program of rocket launches aimed at the solution of several outstanding questions in X-ray astronomy. Of four rocket launches, one was almost totally unsuccessful due to a mechanical failure; one was only partially successful due to a failure of the ACS (Attitude Control System); and two performed as planned. Notwithstanding the delays induced by this run of bad luck, a considerable amount of data has been gathered and analyzed. The major results obtained in the flights on October 11, 1966, and on February 2, 1968, have been published. It is my intent today to report on preliminary results of a recent flight (December 5, 1968) and briefly summarize conclusions from previous flights, and comment on a few selected topics to which this experimental program may contribute.

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“…The most noticeable effect was observed in Cyg X-3 by Gorenstein et al (1967) and the data are shown in Figure 8. We note that also sources The parameters Ea and T represent the best fit.…”

mentioning

confidence: 86%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Properties of individual X-ray sources: (Invited discourse)

Giacconi¹

1970

Symp. - Int. Astron. Union

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“…The X-ray source Cyg X-2 was identified with a variable star, later named V1341 Cyg [1]. Cyg X-2 is a low-mass, close binary system with an accreting neutron star, and is one of the brightest objects of this type in the X-ray.…”

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confidence: 99%

WBVR observations of the X-ray star V1341 Cyg = Cyg X-2 in 1986–1992

Sazonov

2011

Astron. Rep.

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We present the results of W BV R observations of the low-mass X-ray binary V1341 Cyg = Cyg X-2. Our observations include a total of 2375 individual measurements in four bands on 478 nights in 1986-1992. We tied the comparison and check stars used for the binary to the W BV R catalog using their JHK magnitudes. The uncertainty of this procedure was 3% in the B and V bands and 8%-10% for the W and R bands. In quiescence, the amplitude of the periodic component in the binary's B brightness variations is within 0.265 m −0.278; this is due to the ellipsoidal shape of the optical component, which is distorted with gravitational forces from the X-ray component. Some of the system's active states (long flares) may be due to instabilities in the accretion disk, and possibly to instabilities of gas flows and other accretion structures. The binary possesses a low-luminosity accretion disk. The light curves reveal no indications of an eclipse near the phases of the upper and lower conjunctions in quiescence or in active states during the observed intervals. We conclude that the optical star in the close binary V1341 Cyg = Cyg X-2 is a red giant rather than a blue straggler. We studied the long-term variability of the binary during the seven years covered by our observations. The optical observations presented in this study are compared to X-ray data from the Ginga observatory for the same time intervals.

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Galaxian structure and x-ray astronomy

Gursky

1988

The Outer Galaxy

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On the Optical Search for the X-Ray Sources CYG X-1 and CYG X-2

Cited by 49 publications

References 0 publications

Properties of individual X-ray sources: (Invited discourse)

Properties of individual X-ray sources: (Invited discourse)

WBVR observations of the X-ray star V1341 Cyg = Cyg X-2 in 1986–1992

Galaxian structure and x-ray astronomy

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