EXTENDED X-RAY-EMISSION IN NEARBY SEYFERT-GALAXIES

被引:44
作者
ELVIS, M
FASSNACHT, C
WILSON, AS
BRIEL, U
机构
[1] UNIV MARYLAND,ASTRON PROGRAM,COLLEGE PK,MD 20742
[2] MAX PLANCK INST EXTRATERRESTR PHYS,W-8046 GARCHING,GERMANY
关键词
Galaxies: interstellar matter; Galaxies: Seyfert; Galaxies: X-rays; Radiation mechanisms;
D O I
10.1086/169210
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Asymmetric extended X-ray emission has been discovered around two Seyfert nuclei (NGC 1566 and NGC 2992) using the Einstein HRI. Extended X-ray emission is also present in NGC 4151. The emission amounts to 15%-30% of the total HRI X-ray flux and extends over ∼1 kpc. Such extended X-ray emission is presumably a common feature in Seyfert galaxies since it has been found in three out of five Seyferts with sufficiently good HRI data. This extended emission is almost certainly associated with the nuclear activity, since the ratio of its X-ray flux to the B band flux from the same region is two orders of magnitude larger than is typical of early-type spirals. We discuss various possible origins for this emission, including thermal bremsstrahlung, synchrotron radiation, inverse Compton scattering, and electron-scattered nuclear radiation. The present data, while favoring thermal models, are unable to discriminate between them definitively. If the extended X-ray emission is from hot gas, then this gas has a pressure comparable to that required for confinement of both the emission-line clouds in the extended narrow line region and the extended radio sources.
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页码:459 / 469
页数:11
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