High-energy gamma radiation from Geminga observed by EGRET

H. A. Mayer-Hasselwander; D. L. Bertsch; K. T.S. Brazier; J. Chiang; C. E. Fichtel; J. M. Fierro; R. C. Hartman; S. D. Hunter; G. Kanbach; P. W. Kwok; D. A. Kniffen; Y. C. Lin; J. R. Mattox; P. F. Michelson; P. L. Nolan; K. Pinkau; H. Rothermel; E. J. Schneid; M. Sommer; P. Sreekumar; D. J. Thompson; C. Von Montigny

doi:10.1086/173645

High-energy gamma radiation from Geminga observed by EGRET

H. A. Mayer-Hasselwander^*
, D. L. Bertsch
, K. T.S. Brazier
, J. Chiang
, C. E. Fichtel
, J. M. Fierro
, R. C. Hartman
, S. D. Hunter
, G. Kanbach
, P. W. Kwok
, D. A. Kniffen
, Y. C. Lin
, J. R. Mattox
, P. F. Michelson
, P. L. Nolan
, K. Pinkau
, H. Rothermel
, E. J. Schneid
, M. Sommer
, P. Sreekumar

D. J. Thompson, C. Von Montigny

^*Corresponding author for this work

Manipal Centre for Natural Sciences, Manipal

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

76 Citations (Scopus)

Abstract

The Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) has carried out extensive studies of the gamma-ray source Geminga. Following the detection of pulsed X-rays (Halpern & Holt 1992) from Geminga, Bertsch et al. (1992) reported the same 237 ms periodicity to be visible in the EGRET data. A full analysis of the Geminga source shows that the energy spectrum is compatible with a power law with a spectral index of -1.50 ± 0.08 between 30 MeV and 2 GeV. A falloff relative to the power law is observed for energies above 2 GeV. Phase-resolved spectra also show power laws with high-energy cutoffs, but with significant variation of the spectral index with phase. No unpulsed emission is observed. No evidence for time variation was found within the EGRET observations.

Original language	English
Pages (from-to)	276-283
Number of pages	8
Journal	Astrophysical Journal
Volume	421
Issue number	1
DOIs	https://doi.org/10.1086/173645
Publication status	Published - 20-01-1994

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/173645

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Mayer-Hasselwander, H. A., Bertsch, D. L., Brazier, K. T. S., Chiang, J., Fichtel, C. E., Fierro, J. M., Hartman, R. C., Hunter, S. D., Kanbach, G., Kwok, P. W., Kniffen, D. A., Lin, Y. C., Mattox, J. R., Michelson, P. F., Nolan, P. L., Pinkau, K., Rothermel, H., Schneid, E. J., Sommer, M., ... Von Montigny, C. (1994). High-energy gamma radiation from Geminga observed by EGRET. Astrophysical Journal, 421(1), 276-283. https://doi.org/10.1086/173645

@article{7ccd180f21674c2483bd75e65e4932ff,

title = "High-energy gamma radiation from Geminga observed by EGRET",

abstract = "The Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) has carried out extensive studies of the gamma-ray source Geminga. Following the detection of pulsed X-rays (Halpern \& Holt 1992) from Geminga, Bertsch et al. (1992) reported the same 237 ms periodicity to be visible in the EGRET data. A full analysis of the Geminga source shows that the energy spectrum is compatible with a power law with a spectral index of -1.50 ± 0.08 between 30 MeV and 2 GeV. A falloff relative to the power law is observed for energies above 2 GeV. Phase-resolved spectra also show power laws with high-energy cutoffs, but with significant variation of the spectral index with phase. No unpulsed emission is observed. No evidence for time variation was found within the EGRET observations.",

author = "Mayer-Hasselwander, \{H. A.\} and Bertsch, \{D. L.\} and Brazier, \{K. T.S.\} and J. Chiang and Fichtel, \{C. E.\} and Fierro, \{J. M.\} and Hartman, \{R. C.\} and Hunter, \{S. D.\} and G. Kanbach and Kwok, \{P. W.\} and Kniffen, \{D. A.\} and Lin, \{Y. C.\} and Mattox, \{J. R.\} and Michelson, \{P. F.\} and Nolan, \{P. L.\} and K. Pinkau and H. Rothermel and Schneid, \{E. J.\} and M. Sommer and P. Sreekumar and Thompson, \{D. J.\} and \{Von Montigny\}, C.",

year = "1994",

month = jan,

day = "20",

doi = "10.1086/173645",

language = "English",

volume = "421",

pages = "276--283",

journal = "Astrophysical Journal",

issn = "0004-637X",

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number = "1",

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Mayer-Hasselwander, HA, Bertsch, DL, Brazier, KTS, Chiang, J, Fichtel, CE, Fierro, JM, Hartman, RC, Hunter, SD, Kanbach, G, Kwok, PW, Kniffen, DA, Lin, YC, Mattox, JR, Michelson, PF, Nolan, PL, Pinkau, K, Rothermel, H, Schneid, EJ, Sommer, M, Sreekumar, P, Thompson, DJ & Von Montigny, C 1994, 'High-energy gamma radiation from Geminga observed by EGRET', Astrophysical Journal, vol. 421, no. 1, pp. 276-283. https://doi.org/10.1086/173645

TY - JOUR

T1 - High-energy gamma radiation from Geminga observed by EGRET

AU - Mayer-Hasselwander, H. A.

AU - Bertsch, D. L.

AU - Brazier, K. T.S.

AU - Chiang, J.

AU - Fichtel, C. E.

AU - Fierro, J. M.

AU - Hartman, R. C.

AU - Hunter, S. D.

AU - Kanbach, G.

AU - Kwok, P. W.

AU - Kniffen, D. A.

AU - Lin, Y. C.

AU - Mattox, J. R.

AU - Michelson, P. F.

AU - Nolan, P. L.

AU - Pinkau, K.

AU - Rothermel, H.

AU - Schneid, E. J.

AU - Sommer, M.

AU - Sreekumar, P.

AU - Thompson, D. J.

AU - Von Montigny, C.

PY - 1994/1/20

Y1 - 1994/1/20

N2 - The Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) has carried out extensive studies of the gamma-ray source Geminga. Following the detection of pulsed X-rays (Halpern & Holt 1992) from Geminga, Bertsch et al. (1992) reported the same 237 ms periodicity to be visible in the EGRET data. A full analysis of the Geminga source shows that the energy spectrum is compatible with a power law with a spectral index of -1.50 ± 0.08 between 30 MeV and 2 GeV. A falloff relative to the power law is observed for energies above 2 GeV. Phase-resolved spectra also show power laws with high-energy cutoffs, but with significant variation of the spectral index with phase. No unpulsed emission is observed. No evidence for time variation was found within the EGRET observations.

AB - The Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) has carried out extensive studies of the gamma-ray source Geminga. Following the detection of pulsed X-rays (Halpern & Holt 1992) from Geminga, Bertsch et al. (1992) reported the same 237 ms periodicity to be visible in the EGRET data. A full analysis of the Geminga source shows that the energy spectrum is compatible with a power law with a spectral index of -1.50 ± 0.08 between 30 MeV and 2 GeV. A falloff relative to the power law is observed for energies above 2 GeV. Phase-resolved spectra also show power laws with high-energy cutoffs, but with significant variation of the spectral index with phase. No unpulsed emission is observed. No evidence for time variation was found within the EGRET observations.

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SN - 0004-637X

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SP - 276

EP - 283

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

ER -

High-energy gamma radiation from Geminga observed by EGRET

Abstract

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