2003A&A...408..949G -
Astronomy and Astrophysics, volume 408, 949-959 (2003/9-4)
On the origin of the X-rays and the nature of accretion in NGC 4261.
GLIOZZI M., SAMBRUNA R.M. and BRANDT W.N.
Abstract (from CDS):
We report on the X-ray properties of the radio galaxy
NGC 4261, combining information from the XMM-Newton, Chandra, and BeppoSAX satellites. Goals of this study are to investigate the origin of the X-rays from this low-power radio galaxy and the nature of the accretion process onto the central black hole. The X-ray spectrum of the nuclear source extending up to 100-150keV is well described by a partially covered (covering factor >0.8) power law with a photon index Γ≃1.5 absorbed by a column density N
H>5x10
22cm
–2. The X-ray luminosity associated with the non-thermal component is ∼5x10
41erg/s. The nuclear source is embedded in a diffuse hot gas (kT∼0.6-0.65keV), whose density profile implies a Bondi accretion rate of ∼4.5x10
–2M
☉/yr. For the first time rapid X-ray variability is detected in a low-power radio galaxy at more than 99% confidence level. The observed X-ray spectral and variability properties indicate the accretion flow as the most likely origin of the bulk X-ray continuum. This conclusion is strengthened by energetic considerations based on a comparison between the X-ray luminosity and the kinetic power of the jet, which also suggest that the Bondi accretion rate overestimates the actual accretion rate onto the black hole.
Abstract Copyright:
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Journal keyword(s):
galaxies: active - galaxies: nuclei - X-rays: galaxies
Nomenclature:
Table 4: [GSB2003b] A (Nos A-E).
Simbad objects:
16
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