EGRET observations of the BL Lacertae objects 0716 + 714 and 0521-365

Y. C. Lin; D. L. Bertsch; B. L. Dingus; J. A. Esposito; C. E. Fichtel; R. C. Hartman; S. D. Hunter; G. Kanbach; D. A. Kniffen; H. A. Mayer-Hasselwander; P. F. Michelson; C. Von Montigny; R. Mukherjee; P. L. Nolan; E. Schneid; P. Sreekumar; D. J. Thompson

doi:10.1086/175427

EGRET observations of the BL Lacertae objects 0716 + 714 and 0521-365

Y. C. Lin^*, D. L. Bertsch, B. L. Dingus, J. A. Esposito, C. E. Fichtel, R. C. Hartman, S. D. Hunter, G. Kanbach, D. A. Kniffen, H. A. Mayer-Hasselwander, P. F. Michelson, C. Von Montigny, R. Mukherjee, P. L. Nolan, E. Schneid, P. Sreekumar, D. J. Thompson

^*Corresponding author for this work

Manipal Centre for Natural Sciences, Manipal

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Abstract

During the Compton Observatory's viewing programs Phase 1 (1991 April to 1992 November, also known as the All-Sky Survey) and Phase 2 (1992 November to 1993 September), the BL Lac object 0716 + 714 was in the field of view of the EGRET telescope a total of six times, three times in Phase 1 and three more times in Phase 2, while the BL Lac object 0521-365 was in the field of view of EGRET only once in Phase 1. The source 0716 + 714 was detected in high-energy gamma rays by EGRET at a flux level of (2.0 ± 0.4) × 10^-7 photons cm^-2 s^-1 for E > 100 MeV with a 6 σ significance when it was first observed by EGRET in 1992 January 10 to 23. The corresponding spectral slope of the photon number distribution is determined to be -2.04 ± 0.33. The gamma-ray flux of 0716 + 714 showed considerable time variability in subsequent EGRET observations. But the spectral slope stayed about the same within the statistical uncertainties of the EGRET data. The average spectral slope of the four viewing periods during which the photon flux of 0716 + 714 stayed above the EGRET detection threshold is found to be -1.85 ± 0.20 from the combined data. The source 0521 + 365 was detected by EGRET in 1992 May 14 to June 4 at a flux level of (1.8 ± 0.5) × 10^-7 photons cm^-2 s^-1 for E > 100 MeV with a 4 σ significance. The corresponding spectral slope of the photon number distribution is found to be 2.16 ± 0.36. Details of the observations of these two BL Lac objects with the EGRET telescope are presented.

Original language	English
Pages (from-to)	96-104
Number of pages	9
Journal	Astrophysical Journal
Volume	442
Issue number	1
DOIs	https://doi.org/10.1086/175427
Publication status	Published - 20-03-1995

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/175427

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Lin, Y. C., Bertsch, D. L., Dingus, B. L., Esposito, J. A., Fichtel, C. E., Hartman, R. C., Hunter, S. D., Kanbach, G., Kniffen, D. A., Mayer-Hasselwander, H. A., Michelson, P. F., Von Montigny, C., Mukherjee, R., Nolan, P. L., Schneid, E., Sreekumar, P., & Thompson, D. J. (1995). EGRET observations of the BL Lacertae objects 0716 + 714 and 0521-365. Astrophysical Journal, 442(1), 96-104. https://doi.org/10.1086/175427

@article{033173b837ed455496c59135254df4ce,

title = "EGRET observations of the BL Lacertae objects 0716 + 714 and 0521-365",

abstract = "During the Compton Observatory's viewing programs Phase 1 (1991 April to 1992 November, also known as the All-Sky Survey) and Phase 2 (1992 November to 1993 September), the BL Lac object 0716 + 714 was in the field of view of the EGRET telescope a total of six times, three times in Phase 1 and three more times in Phase 2, while the BL Lac object 0521-365 was in the field of view of EGRET only once in Phase 1. The source 0716 + 714 was detected in high-energy gamma rays by EGRET at a flux level of (2.0 ± 0.4) × 10-7 photons cm-2 s-1 for E > 100 MeV with a 6 σ significance when it was first observed by EGRET in 1992 January 10 to 23. The corresponding spectral slope of the photon number distribution is determined to be -2.04 ± 0.33. The gamma-ray flux of 0716 + 714 showed considerable time variability in subsequent EGRET observations. But the spectral slope stayed about the same within the statistical uncertainties of the EGRET data. The average spectral slope of the four viewing periods during which the photon flux of 0716 + 714 stayed above the EGRET detection threshold is found to be -1.85 ± 0.20 from the combined data. The source 0521 + 365 was detected by EGRET in 1992 May 14 to June 4 at a flux level of (1.8 ± 0.5) × 10-7 photons cm-2 s-1 for E > 100 MeV with a 4 σ significance. The corresponding spectral slope of the photon number distribution is found to be 2.16 ± 0.36. Details of the observations of these two BL Lac objects with the EGRET telescope are presented.",

author = "Lin, \{Y. C.\} and Bertsch, \{D. L.\} and Dingus, \{B. L.\} and Esposito, \{J. A.\} and Fichtel, \{C. E.\} and Hartman, \{R. C.\} and Hunter, \{S. D.\} and G. Kanbach and Kniffen, \{D. A.\} and Mayer-Hasselwander, \{H. A.\} and Michelson, \{P. F.\} and \{Von Montigny\}, C. and R. Mukherjee and Nolan, \{P. L.\} and E. Schneid and P. Sreekumar and Thompson, \{D. J.\}",

year = "1995",

month = mar,

day = "20",

doi = "10.1086/175427",

language = "English",

volume = "442",

pages = "96--104",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "1",

}

Lin, YC, Bertsch, DL, Dingus, BL, Esposito, JA, Fichtel, CE, Hartman, RC, Hunter, SD, Kanbach, G, Kniffen, DA, Mayer-Hasselwander, HA, Michelson, PF, Von Montigny, C, Mukherjee, R, Nolan, PL, Schneid, E, Sreekumar, P & Thompson, DJ 1995, 'EGRET observations of the BL Lacertae objects 0716 + 714 and 0521-365', Astrophysical Journal, vol. 442, no. 1, pp. 96-104. https://doi.org/10.1086/175427

TY - JOUR

T1 - EGRET observations of the BL Lacertae objects 0716 + 714 and 0521-365

AU - Lin, Y. C.

AU - Bertsch, D. L.

AU - Dingus, B. L.

AU - Esposito, J. A.

AU - Fichtel, C. E.

AU - Hartman, R. C.

AU - Hunter, S. D.

AU - Kanbach, G.

AU - Kniffen, D. A.

AU - Mayer-Hasselwander, H. A.

AU - Michelson, P. F.

AU - Von Montigny, C.

AU - Mukherjee, R.

AU - Nolan, P. L.

AU - Schneid, E.

AU - Sreekumar, P.

AU - Thompson, D. J.

PY - 1995/3/20

Y1 - 1995/3/20

N2 - During the Compton Observatory's viewing programs Phase 1 (1991 April to 1992 November, also known as the All-Sky Survey) and Phase 2 (1992 November to 1993 September), the BL Lac object 0716 + 714 was in the field of view of the EGRET telescope a total of six times, three times in Phase 1 and three more times in Phase 2, while the BL Lac object 0521-365 was in the field of view of EGRET only once in Phase 1. The source 0716 + 714 was detected in high-energy gamma rays by EGRET at a flux level of (2.0 ± 0.4) × 10-7 photons cm-2 s-1 for E > 100 MeV with a 6 σ significance when it was first observed by EGRET in 1992 January 10 to 23. The corresponding spectral slope of the photon number distribution is determined to be -2.04 ± 0.33. The gamma-ray flux of 0716 + 714 showed considerable time variability in subsequent EGRET observations. But the spectral slope stayed about the same within the statistical uncertainties of the EGRET data. The average spectral slope of the four viewing periods during which the photon flux of 0716 + 714 stayed above the EGRET detection threshold is found to be -1.85 ± 0.20 from the combined data. The source 0521 + 365 was detected by EGRET in 1992 May 14 to June 4 at a flux level of (1.8 ± 0.5) × 10-7 photons cm-2 s-1 for E > 100 MeV with a 4 σ significance. The corresponding spectral slope of the photon number distribution is found to be 2.16 ± 0.36. Details of the observations of these two BL Lac objects with the EGRET telescope are presented.

AB - During the Compton Observatory's viewing programs Phase 1 (1991 April to 1992 November, also known as the All-Sky Survey) and Phase 2 (1992 November to 1993 September), the BL Lac object 0716 + 714 was in the field of view of the EGRET telescope a total of six times, three times in Phase 1 and three more times in Phase 2, while the BL Lac object 0521-365 was in the field of view of EGRET only once in Phase 1. The source 0716 + 714 was detected in high-energy gamma rays by EGRET at a flux level of (2.0 ± 0.4) × 10-7 photons cm-2 s-1 for E > 100 MeV with a 6 σ significance when it was first observed by EGRET in 1992 January 10 to 23. The corresponding spectral slope of the photon number distribution is determined to be -2.04 ± 0.33. The gamma-ray flux of 0716 + 714 showed considerable time variability in subsequent EGRET observations. But the spectral slope stayed about the same within the statistical uncertainties of the EGRET data. The average spectral slope of the four viewing periods during which the photon flux of 0716 + 714 stayed above the EGRET detection threshold is found to be -1.85 ± 0.20 from the combined data. The source 0521 + 365 was detected by EGRET in 1992 May 14 to June 4 at a flux level of (1.8 ± 0.5) × 10-7 photons cm-2 s-1 for E > 100 MeV with a 4 σ significance. The corresponding spectral slope of the photon number distribution is found to be 2.16 ± 0.36. Details of the observations of these two BL Lac objects with the EGRET telescope are presented.

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U2 - 10.1086/175427

DO - 10.1086/175427

M3 - Article

AN - SCOPUS:11944254337

SN - 0004-637X

VL - 442

SP - 96

EP - 104

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

ER -

EGRET observations of the BL Lacertae objects 0716 + 714 and 0521-365

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