2007ApJ...656...84G -
Astrophys. J., 656, 84-92 (2007/February-2)
X-ray properties of intermediate-mass black holes in active galaxies.
GREENE J.E. and HO L.C.
Abstract (from CDS):
We present a pilot study of the X-ray properties of intermediate-mass (∼105-106 M☉) black holes in active galaxies using the Chandra X-ray telescope. Eight of the 10 active galaxies are detected with a significance of at least 3 σ, with X-ray luminosities in the range L_0.5-2 keV_~1041-1043 ergs/s. The optical to X-ray flux ratios are consistent with expectations, given the known correlations between αox and ultraviolet luminosity, while a couple of objects appear to be anomalously X-ray weak. The range of 0.5 to 2 keV photon indices we measure, 1<Γs<2.7, is entirely consistent with values found in samples of more luminous sources with more massive black holes. Black hole mass is evidently not a primary driver of soft X-ray spectral index. On the other hand, we do find evidence for a correlation between the X-ray power-law slope and both X-ray luminosity and Eddington ratio, which may suggest that X-ray emission mechanisms weaken at high Eddington ratios. Such a weakening may explain the anomalous X-ray weakness of one of our most optically luminous objects.
Abstract Copyright:
∼
Journal keyword(s):
Galaxies: Active - Galaxies: Nuclei - Galaxies: Seyfert - X-Rays: Galaxies
Simbad objects:
14
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2007ApJ...656...84G and select 'bookmark this link' or equivalent in the popup menu