Gamma-ray observations of cygnus X-1 with the oriented scintillation spectrometer experiment

B. F. Phlips; G. V. Jung; M. D. Leising; J. E. Grove; W. N. Johnson; R. L. Kinzer; R. A. Kroeger; J. D. Kurfess; M. S. Strickman; D. A. Grabelsky; S. M. Matz; W. R. Purcell; M. P. Ulmer; K. Mcnaron-Brown

doi:10.1086/177474

Gamma-ray observations of cygnus X-1 with the oriented scintillation spectrometer experiment

B. F. Phlips^*, G. V. Jung, M. D. Leising, J. E. Grove, W. N. Johnson, R. L. Kinzer, R. A. Kroeger, J. D. Kurfess, M. S. Strickman, D. A. Grabelsky, S. M. Matz, W. R. Purcell, M. P. Ulmer, K. Mcnaron-Brown

^*Corresponding author for this work

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

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Abstract

We report on ∼ 120 days of observations of Cygnus X-1 with OSSE on board the Compton Gamma Ray Observatory. Emission is detected in the range 50 keV-1 MeV, and we find evidence for a continuum of hard X-ray flux levels rather than the existence of distinct flux states. Comparisons of the source spectra with various theoretical models show that an exponentially truncated power law best describes the average spectrum in the OSSE energy band. Although we have measured a new minimum in the hard X-ray flux from the source, no evidence was found for either a broad 1 MeV feature or a narrow 511 keV line, previously reported in association with a low flux state. Upper limits on such emission features are an order of magnitude lower than earlier reported detections. The 5.6 day periodicity of the source measured at optical wavelengths was not detected with a sensitivity to the rms modulation fraction of 5% in the 60-140 keV energy band.

Original language	English (US)
Pages (from-to)	907-914
Number of pages	8
Journal	Astrophysical Journal
Volume	465
Issue number	2 PART I
DOIs	https://doi.org/10.1086/177474
State	Published - 1996

Keywords

Gamma rays: observations
Stars: individual (Cygnus X-1)
Stars: oscillations
X-rays: stars

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/177474

Cite this

Phlips, B. F., Jung, G. V., Leising, M. D., Grove, J. E., Johnson, W. N., Kinzer, R. L., Kroeger, R. A., Kurfess, J. D., Strickman, M. S., Grabelsky, D. A., Matz, S. M., Purcell, W. R., Ulmer, M. P., & Mcnaron-Brown, K. (1996). Gamma-ray observations of cygnus X-1 with the oriented scintillation spectrometer experiment. Astrophysical Journal, 465(2 PART I), 907-914. https://doi.org/10.1086/177474

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title = "Gamma-ray observations of cygnus X-1 with the oriented scintillation spectrometer experiment",

abstract = "We report on ∼ 120 days of observations of Cygnus X-1 with OSSE on board the Compton Gamma Ray Observatory. Emission is detected in the range 50 keV-1 MeV, and we find evidence for a continuum of hard X-ray flux levels rather than the existence of distinct flux states. Comparisons of the source spectra with various theoretical models show that an exponentially truncated power law best describes the average spectrum in the OSSE energy band. Although we have measured a new minimum in the hard X-ray flux from the source, no evidence was found for either a broad 1 MeV feature or a narrow 511 keV line, previously reported in association with a low flux state. Upper limits on such emission features are an order of magnitude lower than earlier reported detections. The 5.6 day periodicity of the source measured at optical wavelengths was not detected with a sensitivity to the rms modulation fraction of 5\% in the 60-140 keV energy band.",

keywords = "Gamma rays: observations, Stars: individual (Cygnus X-1), Stars: oscillations, X-rays: stars",

author = "Phlips, \{B. F.\} and Jung, \{G. V.\} and Leising, \{M. D.\} and Grove, \{J. E.\} and Johnson, \{W. N.\} and Kinzer, \{R. L.\} and Kroeger, \{R. A.\} and Kurfess, \{J. D.\} and Strickman, \{M. S.\} and Grabelsky, \{D. A.\} and Matz, \{S. M.\} and Purcell, \{W. R.\} and Ulmer, \{M. P.\} and K. Mcnaron-Brown",

year = "1996",

doi = "10.1086/177474",

language = "English (US)",

volume = "465",

pages = "907--914",

journal = "Astrophysical Journal",

issn = "0004-637X",

number = "2 PART I",

}

Phlips, BF, Jung, GV, Leising, MD, Grove, JE, Johnson, WN, Kinzer, RL, Kroeger, RA, Kurfess, JD, Strickman, MS, Grabelsky, DA, Matz, SM, Purcell, WR, Ulmer, MP & Mcnaron-Brown, K 1996, 'Gamma-ray observations of cygnus X-1 with the oriented scintillation spectrometer experiment', Astrophysical Journal, vol. 465, no. 2 PART I, pp. 907-914. https://doi.org/10.1086/177474

TY - JOUR

T1 - Gamma-ray observations of cygnus X-1 with the oriented scintillation spectrometer experiment

AU - Phlips, B. F.

AU - Jung, G. V.

AU - Leising, M. D.

AU - Grove, J. E.

AU - Johnson, W. N.

AU - Kinzer, R. L.

AU - Kroeger, R. A.

AU - Kurfess, J. D.

AU - Strickman, M. S.

AU - Grabelsky, D. A.

AU - Matz, S. M.

AU - Purcell, W. R.

AU - Ulmer, M. P.

AU - Mcnaron-Brown, K.

PY - 1996

Y1 - 1996

N2 - We report on ∼ 120 days of observations of Cygnus X-1 with OSSE on board the Compton Gamma Ray Observatory. Emission is detected in the range 50 keV-1 MeV, and we find evidence for a continuum of hard X-ray flux levels rather than the existence of distinct flux states. Comparisons of the source spectra with various theoretical models show that an exponentially truncated power law best describes the average spectrum in the OSSE energy band. Although we have measured a new minimum in the hard X-ray flux from the source, no evidence was found for either a broad 1 MeV feature or a narrow 511 keV line, previously reported in association with a low flux state. Upper limits on such emission features are an order of magnitude lower than earlier reported detections. The 5.6 day periodicity of the source measured at optical wavelengths was not detected with a sensitivity to the rms modulation fraction of 5% in the 60-140 keV energy band.

AB - We report on ∼ 120 days of observations of Cygnus X-1 with OSSE on board the Compton Gamma Ray Observatory. Emission is detected in the range 50 keV-1 MeV, and we find evidence for a continuum of hard X-ray flux levels rather than the existence of distinct flux states. Comparisons of the source spectra with various theoretical models show that an exponentially truncated power law best describes the average spectrum in the OSSE energy band. Although we have measured a new minimum in the hard X-ray flux from the source, no evidence was found for either a broad 1 MeV feature or a narrow 511 keV line, previously reported in association with a low flux state. Upper limits on such emission features are an order of magnitude lower than earlier reported detections. The 5.6 day periodicity of the source measured at optical wavelengths was not detected with a sensitivity to the rms modulation fraction of 5% in the 60-140 keV energy band.

KW - Gamma rays: observations

KW - Stars: individual (Cygnus X-1)

KW - Stars: oscillations

KW - X-rays: stars

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DO - 10.1086/177474

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VL - 465

SP - 907

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JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 PART I

ER -

Gamma-ray observations of cygnus X-1 with the oriented scintillation spectrometer experiment

Abstract

Keywords

ASJC Scopus subject areas

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