Andrzej Zdziarski, W. Neil Johnson, Chris Done, David Smith, Kellie Mcnaron-brown
We have obtained the first average 2--500 keV spectra of Seyfert galaxies, using the data from Ginga and GRO OSSE. Our sample contains 3 classes of objects with markedly different spectra:...
Seyferts and Radio Galaxies (2007)
Neil Johnson Andrzej, W. Neil Johnson, Andrzej A. Zdziarski, Greg M. Madejski, William S. Paciesas, Ying-chi Lin
. Observations with Compton Gamma Ray Observatory have provided key insights to the high energy emission mechanisms in Active Galactic Nuclei (AGN) and clearly separate them into a class of Blazars,...
Limits on Nuclear Gamma-Ray Emission from Orion (2007)
Ronald Murphy, Gerald H. Share, J. Eric Grove, W. Neil Johnson, James D. Kurfess, William R. Purcell, ...
The discovery of fl-ray line emission in the 3 -- 7 MeV range from the Orion complex was recently reported (Bloemen et al. 1994). The observed Compton Telescope (COMPTEL) spectrum suggested that the...
Fl-Ray Spectra, Andrzej A. Zdziarski, David Smith, Greg M. Madejski, W. Neil Johnson
We study X-ray and soft fl-ray spectral properties of nearby Broad-Line Radio Galaxies (BLRGs) using data from Ginga, ASCA, OSSE and EXOSAT. The X-ray spectra are well fitted by an intrinsic...
X-ray and gamma-ray spectra and variability of the black-hole candidate GX 339-4 (2002)
Wardzinski, Grzegorz, Zdziarski, Andrzej A., Gierlinski, Marek, Grove, J. Eric, Jahoda, Keith, Johnson, W. Neil
We analyse five observations of the X-ray binary GX 339-4 by the soft gamma-ray OSSE detector on board CGRO simultaneous with either Ginga or RXTE observations. The source was bright during four of...
Observations of Seyferts by OSSE and parameters of their X-ray/gamma-ray sources (2000)
Zdziarski, Andrzej A., Poutanen, Juri, Johnson, W. Neil
We present a summary of spectra of Seyfert galaxies observed by the OSSE detector aboard Compton Gamma Ray Observatory. We obtain average spectra of Seyferts of type 1 and 2, and find they are well...
Zdziarski, Andrzej A., Poutanen, Juri, Mikolajewska, Joanna, Gierlinski, Marek, Ebisawa, Ken, Johnson, W. Neil
We present X-ray/gamma-ray spectra of the binary GX 339-4 observed in the hard state simultaneously by Ginga and CGRO OSSE during an outburst in 1991 September. The Ginga spectra are well represented...
X-ray and soft gamma-ray spectra of Broad-Line Radio Galaxies (1998)
Wozniak, Przemyslaw R., Zdziarski, Andrzej A., Smith, David, Madejski, Greg M., Johnson, W. Neil
We study X-ray and soft gamma-ray spectral properties of BLRGs using data from Ginga, ASCA, OSSE and EXOSAT. The X-ray spectra are well fitted by an intrinsic power-law continuum with an energy index...
X-ray and gamma-ray spectra of Cyg X-1 in the soft state (1997)
Gierlinski, Marek, Zdziarski, Andrzej A., Dotani, Tadayasu, Ebisawa, Ken, Jahoda, Keith, Johnson, W. Neil
We present X-ray/gamma-ray observations of Cyg X-1 in the soft state during 1996 May-June. We analyze ASCA, RXTE and OSSE data. The spectrum consists of soft X-ray blackbody emission of an optically...
X-rays and gamma-rays from accretion flows onto black holes in Seyferts and X-ray binaries (1996)
Zdziarski, Andrzej A., Johnson, W. Neil, Poutanen, Juri, Magdziarz, Pawel, Gierlinski, Marek
We review observations and theoretical models of X-ray/gamma-ray spectra of radio-quiet Seyfert galaxies and of Galactic black-hole candidates (in the hard spectral state). The observed spectra share...
Simultaneous X-ray and gamma-ray observations of Cyg X-1 in the hard state by Ginga and OSSE (1996)
Gierlinski, Marek, Zdziarski, Andrzej A., Done, Chris, Johnson, W. Neil, Ebisawa, Ken, Ueda, Yoshihiro, ...
We present four X-ray/gamma-ray spectra of Cyg X-1 observed in the hard ('low') state simultaneously by Ginga and GRO/OSSE on 1991 July 6. The 3-30 keV Ginga spectra are well represented by power...
The first simultaneous X-ray/gamma-ray observations of Cyg X-1 by Ginga and OSSE (1995)
Gierlinski, Marek, Zdziarski, Andrzej A., Johnson, W. Neil, Phlips, Bernard F., Ebisawa, Ken, Done, Chris
We present the results of 4 simultaneous observations of Cygnus X-1 by Ginga and OSSE. The X-ray/gamma-ray spectra can be described by an intrinsic continuum and a component due to Compton reflection...