Detection of Gamma Radiation from the Cygnus Region

Haymes, R. C.; Ellis, Darwin V.; Fishman, G.; Glenn, S. W.; Kurfess, J. D.

doi:10.1086/180156

Cited by 25 publications

(13 citation statements)

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“…Dolan (1970) has summarized these in his review and a large number of papers have been referred there. Dolan (1970) gives the following spectral forms as typical and many observed spectra agree with them: Between 35-123 KeV (Haymes et al, 1968) dN 42 4-0.58) E -1"8~ photons cm -2 s -1 KeV -1 (1) dE = (3.…”

Section: Iii31 X-ray Observationsmentioning

confidence: 65%

Celestial binary X-ray sources

Apparao

Chitre

1976

Space Sci Rev

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Section: Iii31 X-ray Observationsmentioning

confidence: 65%

Celestial binary X-ray sources

Apparao

Chitre

1976

Space Sci Rev

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“…Time variations have been reported for this source and the large scatter of the rocket data indicates that this is indeed the case. The UCSD observations do not presently extend to high enough energy to verify the break in the spectrum at about 150 keV reported by Haymes (Haymes et al, 1968b). The spectrum of the weak source Cygnus XR-3 has also been determined on a balloon flight on 22 May, 1968.…”

Section: Id 4 -mentioning

confidence: 97%

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

Peterson

1970

Symp. - Int. Astron. Union

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Abstract. Observations to determine the spectra and time variations of hard X-rays from cosmic sources have been made from balloons and from the OSO-III satellite. These data have been obtained using actively collimated scintillation counters with apertures between 6 and 24° FWHM, areas between 10 and 50 cm 2 and which operate over the 10-300 keV range. The Crab Nebula has been observed on three occasions over a 22-month period between September 1965 and July 1967. The power law spectrum has a number index of 2.0 ± 0.1. No long-term changes were observed over the 30-100keV range with a limit at 3%/yr. A balloon search with a 10 cm 2 Ge(Li) detector for X-ray lines at 62.5 keV, 110 keV and 180 keV due to heavy element radioactive decays which would be produced in the initial Crab explosion based on the Cf 254 hypothesis has resulted in upper limits at about 10" 3 y-rays cm 2 -sec. This is about a factor of 20 above the predicted levels. Simultaneous X-ray and optical observations of SCO XR-1 from OSO-III confirm that X-ray and optical flaring are indeed coincident phenomena, and that although the X-ray intensity increases about a factor of two during the flare, the equivalent temperature of the excess radiation is nearly the same as that of the quiescent object. Upper limits, 95% confidence, on the flux of M-87 at 40 keV have been obtained. These are inconsistent with the flux of 1.2 x 10~4 photons/cm 2 -sec-keV reported in the literature. CYG X-l has been observed to have a power law of number index 2.0 ± 0.2. The OSO-III has observed a number of sources in the southern skies including NOR XR-2 and the variable source Centaurus XR-2.

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“…The best observations on which to base such a theoretical spectrum, by necessity, are those of the highest spectral resolution. Perhaps the best observation of Cyg XR-1 in terms of energy resolution is that of Haymes et al (1968), who found that between 35 and 123 keV the photon flux could be approximated by a spectrum characteristic of synchrotron radiation dN dE -(3.42 -t-0.58) E-j'8~ photons cm-2 sec-1 keV-1…”

Section: Spectra Of Cyg Xr-i Derived From Flux Observationsmentioning

confidence: 99%

“…The flight was launched on May 16, 1967, and the siderial time of observation is stated to be 2250-2330 (Overbeck and Tananbaum, 1968b), although the longitude at which this is the siderial time is not stated. From I I I III I I I I IIIII I I I I II I I I I I I I III I 1 I I I I III I I I I I I x • I I I I I III [ I I I I II11 I I I 1 # I I I I I I I I III I I I I I I I I I I I I II I I I I I I III I x, I I 11 I I lO 100 I000 E (Kevl The observations of Haymes et al (1968). Not all of the data obtained by Haymes et al are included in this figure, but the points given are representative of the data.…”

Section: -Imentioning

confidence: 99%

“…The observations in Figures 19 and 20 both appear to be consistent with the spectrum given by Equation (1), although slightly more than one standard deviation above it; the observations contained in Figure 21, however, are within one standard deviation in the count rate of Equation (4) but more than one standard deviation from the spectrum represented by Equation (1). Figure 22 presents the results of Haymes et al (1968), taken with an actively collimated NaI scintillation detector flown aboard a balloon. The instrument was alternately pointed at the source and at a region 180 ~ away in aximuth every 10 min.…”

Section: -Imentioning

confidence: 99%

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The variable X-ray spectrum of Cyg XR-1

Dolan

1970

Space Sci Rev

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The variability of the X-ray spectrum of the discrete source Cyg XR-1 (c~ = 19 h 56m) = q-35~ is reviewed. The variations observed in the energy region accessible to balloon borne detectors (energies greater than 20 keV) can be explained by assuming them to be caused by the eclipsing properties of a binary system. It is suggested that the system is composed of a source of small angular extent having a spectrum similar to that of a black body at approximately 1.5 x 108 K (kT= 12.5 keV) and a non X-radiating companion which eclipses it at intervals of 2.9850 days. The system would be surrounded by an X-radiating plasma whose photon flux between 1 and 100 keV can be approximated by a power law spectrum whose exponent is --1.7.The discrete X-ray source located at e= 19h56 m, 6= +35.~ and ordinarily designated as Cyg XR-1 (Friedman et al., 1967) is one of the brightest celestial objects in the X-ray region above 20 keV. Because of this, observations have been made of the object since 1964 by balloon borne detectors as well as by rocket borne instrumentation. Although the first observations of the object in the X-ray region below 10 keV led Byram et al. (1966) to make the suggestion that the source was of variable intensity, a more frequent series of measurements taken by balloon borne equipment gave the first convincing proof of the intrinsic variability of the object (see Overbeck and Tananbaum, 1968a), at least in the region above 20 keV. It is profitable to review the variability of the object in the energy regions specified above from the standpoint of deciding whether any regularity, either in spectral shape vs. intensity or in intensity vs. time, can be deduced from the observations.

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Detection of Gamma Radiation from the Cygnus Region

Cited by 25 publications

References 0 publications

Celestial binary X-ray sources

Celestial binary X-ray sources

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

The variable X-ray spectrum of Cyg XR-1

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