Astronomy and Astrophysics – Astrophysics
Scientific paper
1998-05-12
Astronomy and Astrophysics
Astrophysics
20 pages, 13 figures, to appear in MNRAS
Scientific paper
10.1046/j.1365-8711.1998.01831.x
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 of alpha ~ 0.7, moderately absorbed by a cold medium. In addition, the Ginga spectra show Fe K-alpha lines with an average equivalent width of ~ 100 eV, and, in some cases, Compton reflection humps. However, the latter components are significantly weaker than both those seen in radio-quiet Seyferts and those expected if the Fe K-alpha lines were due to reflection. Some ASCA and EXOSAT spectra show soft X-ray excesses below ~ 3 keV. When that component is taken into account, the Fe K-alpha lines in the ASCA data become unresolved with equivalent widths < 200 eV. Multiple observations of 3C 390.3 and 3C 382 show the Fe K-alpha line approximately constant in flux but accompanied by strong continuum variations. This indicates the bulk of the line is formed by matter at a distance much larger than an accretion-disk scale, consistent with the ASCA line width measurements. The column density of the matter required to account for the observed line fluxes is N_H > 10^23 cm^-2. Such a medium is in the line-of-sight in 3C 445 but it has to be out of it in other objects, in which the observed N_H are substantially lower. Thus, a cold medium with that N_H and covering a large solid angle is out of the line-of-sight in most objects. The spectra of BLRGs break and become softer above ~ 100 keV, as shown by a simultaneous ASCA/OSSE observation of 3C 120 and by the OSSE spectra being on average much softer than the X-ray spectra. Finally, we find the X-ray and gamma-ray spectral properties of Cen A intrinsically very similar to BLRGs studied here.
Johnson Neil W.
Madejski Greg M.
Smith David
Wozniak Przemyslaw R.
Zdziarski Andrzej A.
No associations
LandOfFree
X-ray and soft gamma-ray spectra of Broad-Line Radio Galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with X-ray and soft gamma-ray spectra of Broad-Line Radio Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-ray and soft gamma-ray spectra of Broad-Line Radio Galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-635769