OSSE Observations of NGC 4151
Abstract
We report results of a two-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 plus or minus 2 keV in the energy range 65 - 300 keV, and an intensity at 100 keV of (2.33 plus or minus 0.05) x 10 (exp -5) photons /sq cm s (exp -1) keV(exp -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 (chi(exp 2) probability ~7 x 10(exp 4)) simple pair cascade models in a compact source which have been suggested for Seyfert galaxies.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1992
- Accession Number
- ADA461894
Entities
People
- D. A> Grabelsky
- G. V. Jung
- J. D. Kurfess
- M. Maisack
- M. P. Ulmer
- M. S> Strickman
- R. A. Cameron
- R. L. Kinzer
- W. N. Johnson
- W. R. Purcell
Organizations
- George Mason University