Observations of NGC 4151 at 2 keV to 2 MeV from HEAO 1

W. A. Baity; D. M. Worrall; R. E. Rothschild; R. F. Mushotzky; A. F. Tennant; F. A. Primini

Observations of NGC 4151 at 2 keV to 2 MeV from HEAO 1

W. A. Baity, D. M. Worrall, R. E. Rothschild, R. F. Mushotzky, A. F. Tennant, F. A. Primini

School of Physics

Research output: Contribution to journal › Article (Academic Journal) › peer-review

Abstract

Broad-range X-ray and gamma-ray spectra of the Seyfert galaxy NGC 4151 obtained by the UCSD/MIT and GSFC/CIT detectors of HEAO 1 are presented. For two out of the three observational epochs the best-fit model is a power law with photon index 1.6 + or - 0.1 in the 2 keV-2 MeV spectral range. The third observation, in June, 1978, when the intensity was a factor of 2 higher, requires a change above 50 keV from a similar power law to a steeper power law or an exponential. Through comparisons with previous observations, a weak correlation is found between the high-energy spectral index and the flux level. Comparison of these data and other X-ray and gamma-ray observations with the spectra expected from several possible emission mechanisms supports a synchrotron-self-Compton model using infrared target photons or a Compton-scattering process involving X-rays of less than 10 keV energies.

Original language	English
Pages (from-to)	555-562
Journal	Astrophysical Journal
Volume	279
Publication status	Published - 1 Apr 1984

Keywords

Gamma Ray Astronomy
Seyfert Galaxies
Spaceborne Astronomy
X Ray Spectra
Black Holes (Astronomy)
Energy Spectra
Galactic Nuclei
Gamma Ray Spectra
Heao 1
Power Spectra
Synchrotron Radiation

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http://adsabs.harvard.edu/abs/1984ApJ...279..555B

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@article{47d83ef9d2cc44dd95e2bd4e51ca8b69,

title = "Observations of NGC 4151 at 2 keV to 2 MeV from HEAO 1",

abstract = "Broad-range X-ray and gamma-ray spectra of the Seyfert galaxy NGC 4151 obtained by the UCSD/MIT and GSFC/CIT detectors of HEAO 1 are presented. For two out of the three observational epochs the best-fit model is a power law with photon index 1.6 + or - 0.1 in the 2 keV-2 MeV spectral range. The third observation, in June, 1978, when the intensity was a factor of 2 higher, requires a change above 50 keV from a similar power law to a steeper power law or an exponential. Through comparisons with previous observations, a weak correlation is found between the high-energy spectral index and the flux level. Comparison of these data and other X-ray and gamma-ray observations with the spectra expected from several possible emission mechanisms supports a synchrotron-self-Compton model using infrared target photons or a Compton-scattering process involving X-rays of less than 10 keV energies.",

keywords = "Gamma Ray Astronomy, Seyfert Galaxies, Spaceborne Astronomy, X Ray Spectra, Black Holes (Astronomy), Energy Spectra, Galactic Nuclei, Gamma Ray Spectra, Heao 1, Power Spectra, Synchrotron Radiation",

author = "Baity, {W. A.} and Worrall, {D. M.} and Rothschild, {R. E.} and Mushotzky, {R. F.} and Tennant, {A. F.} and Primini, {F. A.}",

year = "1984",

month = apr,

day = "1",

language = "English",

volume = "279",

pages = "555--562",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

}

TY - JOUR

T1 - Observations of NGC 4151 at 2 keV to 2 MeV from HEAO 1

AU - Baity, W. A.

AU - Worrall, D. M.

AU - Rothschild, R. E.

AU - Mushotzky, R. F.

AU - Tennant, A. F.

AU - Primini, F. A.

PY - 1984/4/1

Y1 - 1984/4/1

N2 - Broad-range X-ray and gamma-ray spectra of the Seyfert galaxy NGC 4151 obtained by the UCSD/MIT and GSFC/CIT detectors of HEAO 1 are presented. For two out of the three observational epochs the best-fit model is a power law with photon index 1.6 + or - 0.1 in the 2 keV-2 MeV spectral range. The third observation, in June, 1978, when the intensity was a factor of 2 higher, requires a change above 50 keV from a similar power law to a steeper power law or an exponential. Through comparisons with previous observations, a weak correlation is found between the high-energy spectral index and the flux level. Comparison of these data and other X-ray and gamma-ray observations with the spectra expected from several possible emission mechanisms supports a synchrotron-self-Compton model using infrared target photons or a Compton-scattering process involving X-rays of less than 10 keV energies.

AB - Broad-range X-ray and gamma-ray spectra of the Seyfert galaxy NGC 4151 obtained by the UCSD/MIT and GSFC/CIT detectors of HEAO 1 are presented. For two out of the three observational epochs the best-fit model is a power law with photon index 1.6 + or - 0.1 in the 2 keV-2 MeV spectral range. The third observation, in June, 1978, when the intensity was a factor of 2 higher, requires a change above 50 keV from a similar power law to a steeper power law or an exponential. Through comparisons with previous observations, a weak correlation is found between the high-energy spectral index and the flux level. Comparison of these data and other X-ray and gamma-ray observations with the spectra expected from several possible emission mechanisms supports a synchrotron-self-Compton model using infrared target photons or a Compton-scattering process involving X-rays of less than 10 keV energies.

KW - Gamma Ray Astronomy

KW - Seyfert Galaxies

KW - Spaceborne Astronomy

KW - X Ray Spectra

KW - Black Holes (Astronomy)

KW - Energy Spectra

KW - Galactic Nuclei

KW - Gamma Ray Spectra

KW - Heao 1

KW - Power Spectra

KW - Synchrotron Radiation

M3 - Article (Academic Journal)

VL - 279

SP - 555

EP - 562

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

ER -