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Review of GRANAT Observations of AGNs

Published online by Cambridge University Press:  19 July 2016

E. Churazov
Affiliation:
Space Research Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
M. Gilfanov
Affiliation:
Space Research Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
A. Finoguenov
Affiliation:
Space Research Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
R. Sunyaev
Affiliation:
Space Research Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
M. Chernyakova
Affiliation:
Space Research Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
Yu. Apalkov
Affiliation:
Space Research Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
S. Grebenev
Affiliation:
Space Research Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
I. Lagunov
Affiliation:
Space Research Institute, Profsoyuznaya 84/32, 117810 Moscow, Russia
E. Jourdain
Affiliation:
Centre d'Etude Spatiale des Rayonnements, 9, avenu du Colonel Roche, BP 4346, 31029 Toulouse Cedex, France
J.P. Roques
Affiliation:
Centre d'Etude Spatiale des Rayonnements, 9, avenu du Colonel Roche, BP 4346, 31029 Toulouse Cedex, France
P. Mandrou
Affiliation:
Centre d'Etude Spatiale des Rayonnements, 9, avenu du Colonel Roche, BP 4346, 31029 Toulouse Cedex, France
L. Bouchet
Affiliation:
Centre d'Etude Spatiale des Rayonnements, 9, avenu du Colonel Roche, BP 4346, 31029 Toulouse Cedex, France
J. Ballet
Affiliation:
Service d'Astrophysique, Centre d'Etudes Nucleaires de Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France
A. Claret
Affiliation:
Service d'Astrophysique, Centre d'Etudes Nucleaires de Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France
P. Laurent
Affiliation:
Service d'Astrophysique, Centre d'Etudes Nucleaires de Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France
F. Lebrun
Affiliation:
Service d'Astrophysique, Centre d'Etudes Nucleaires de Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France

Abstract

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Brief review of AGNs observations in the X-ray / soft gamma-ray bands with the orbital observatory GRANAT is presented.

For three well known bright objects (3C273, NGC4151 and Cen A) broad band (3 keV–few hundreds keV) spectra have been obtained. Imaging capabilities allowed accurate (several arcminutes) identification of these objects with sources of hard X-rays.

The spectrum of NGC4151 above ≈ 50 keV was found to be much steeper than that in most of the previous observations, while in standard X-ray band the spectrum agrees with observed previously. The comparison of the observed spectra with that of the X-Ray Background (XRB) indicates that sources similar to NGC4151 could reproduce the shape of XRB spectrum in 3–60 keV band.

Cen A was observed in the very low state during most of observations in 1990–1993, except for two observations in 1991. The variability of the hard X-ray flux has been detected on the time scales of several days.

Keywords

Type
New Observations of AGN with Specific Instruments
Copyright
Copyright © Kluwer 1994 

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