OSSE observations of NGC 4151

M. Maisack; W. N. Johnson; R. L. Kinzer; M. S. Strickman; J. D. Kurfess; R. A. Cameron; G. V. Jung; D. A. Grabelsky; W. R. Purcell; M. P. Ulmer

doi:10.1086/186806

OSSE observations of NGC 4151

M. Maisack^*, W. N. Johnson, R. L. Kinzer, M. S. Strickman, J. D. Kurfess, R. A. Cameron, G. V. Jung, D. A. Grabelsky, W. R. Purcell, M. P. Ulmer

^*Corresponding author for this work

Physics and Astronomy

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

68 Scopus citations

Abstract

We report results of a 2 week observation of the Seyfert galaxy NGC 4151 with the Oriented Scintillation Spectrometer Experiment (OSSE) instrument on the Compton Gamma Ray Observatory (GRO). The source had a very soft spectrum which is best represented by a broken power law or Sunyaev-Titarchuk thermal Comptonization model. It can be characterized by an exponential shape with an e-folding energy of 39 ± 2 keV in the energy range 65-300 keV, and an intensity at 100 keV of (2.33 ±0.05) × 10^-5 photons cm^-2 s^-1 keV^-1. Source intensity variability of ∼25% was observed during the 14 days of our observations; no significant change in spectral shape was detected for this period. The steepness and shape of the spectrum above 100 keV rule out (χ² probability ∼7 × 10^-4) simple pair cascade models in a compact source which have been suggested for Seyfert galaxies.

Original language	English (US)
Pages (from-to)	L61-L64
Journal	Astrophysical Journal
Volume	407
Issue number	2 PART II
DOIs	https://doi.org/10.1086/186806
State	Published - 1993

Keywords

Galaxies: Seyfert
Galaxies: individual (NGC 4151)
Gamma rays: observations

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

Access to Document

10.1086/186806

Cite this

@article{80b5636af5ef4eceabc501191adb34f0,

title = "OSSE observations of NGC 4151",

abstract = "We report results of a 2 week observation of the Seyfert galaxy NGC 4151 with the Oriented Scintillation Spectrometer Experiment (OSSE) instrument on the Compton Gamma Ray Observatory (GRO). The source had a very soft spectrum which is best represented by a broken power law or Sunyaev-Titarchuk thermal Comptonization model. It can be characterized by an exponential shape with an e-folding energy of 39 ± 2 keV in the energy range 65-300 keV, and an intensity at 100 keV of (2.33 ±0.05) × 10-5 photons cm-2 s-1 keV-1. Source intensity variability of ∼25% was observed during the 14 days of our observations; no significant change in spectral shape was detected for this period. The steepness and shape of the spectrum above 100 keV rule out (χ2 probability ∼7 × 10-4) simple pair cascade models in a compact source which have been suggested for Seyfert galaxies.",

keywords = "Galaxies: Seyfert, Galaxies: individual (NGC 4151), Gamma rays: observations",

author = "M. Maisack and Johnson, {W. N.} and Kinzer, {R. L.} and Strickman, {M. S.} and Kurfess, {J. D.} and Cameron, {R. A.} and Jung, {G. V.} and Grabelsky, {D. A.} and Purcell, {W. R.} and Ulmer, {M. P.}",

year = "1993",

doi = "10.1086/186806",

language = "English (US)",

volume = "407",

pages = "L61--L64",

journal = "Astrophysical Journal",

issn = "0004-637X",

number = "2 PART II",

}

TY - JOUR

T1 - OSSE observations of NGC 4151

AU - Maisack, M.

AU - Johnson, W. N.

AU - Kinzer, R. L.

AU - Strickman, M. S.

AU - Kurfess, J. D.

AU - Cameron, R. A.

AU - Jung, G. V.

AU - Grabelsky, D. A.

AU - Purcell, W. R.

AU - Ulmer, M. P.

PY - 1993

Y1 - 1993

N2 - We report results of a 2 week observation of the Seyfert galaxy NGC 4151 with the Oriented Scintillation Spectrometer Experiment (OSSE) instrument on the Compton Gamma Ray Observatory (GRO). The source had a very soft spectrum which is best represented by a broken power law or Sunyaev-Titarchuk thermal Comptonization model. It can be characterized by an exponential shape with an e-folding energy of 39 ± 2 keV in the energy range 65-300 keV, and an intensity at 100 keV of (2.33 ±0.05) × 10-5 photons cm-2 s-1 keV-1. Source intensity variability of ∼25% was observed during the 14 days of our observations; no significant change in spectral shape was detected for this period. The steepness and shape of the spectrum above 100 keV rule out (χ2 probability ∼7 × 10-4) simple pair cascade models in a compact source which have been suggested for Seyfert galaxies.

AB - We report results of a 2 week observation of the Seyfert galaxy NGC 4151 with the Oriented Scintillation Spectrometer Experiment (OSSE) instrument on the Compton Gamma Ray Observatory (GRO). The source had a very soft spectrum which is best represented by a broken power law or Sunyaev-Titarchuk thermal Comptonization model. It can be characterized by an exponential shape with an e-folding energy of 39 ± 2 keV in the energy range 65-300 keV, and an intensity at 100 keV of (2.33 ±0.05) × 10-5 photons cm-2 s-1 keV-1. Source intensity variability of ∼25% was observed during the 14 days of our observations; no significant change in spectral shape was detected for this period. The steepness and shape of the spectrum above 100 keV rule out (χ2 probability ∼7 × 10-4) simple pair cascade models in a compact source which have been suggested for Seyfert galaxies.

KW - Galaxies: Seyfert

KW - Galaxies: individual (NGC 4151)

KW - Gamma rays: observations

UR - http://www.scopus.com/inward/record.url?scp=4244077864&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=4244077864&partnerID=8YFLogxK

U2 - 10.1086/186806

DO - 10.1086/186806

M3 - Article

AN - SCOPUS:4244077864

SN - 0004-637X

VL - 407

SP - L61-L64

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 PART II

ER -

OSSE observations of NGC 4151

Abstract

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this