ROSAT PSPC OBSERVATIONS OF NGC-7469 AND ARK-120

被引:22
作者
BRANDT, WN [1 ]
FABIAN, AC [1 ]
NANDRA, K [1 ]
TSURUTA, S [1 ]
机构
[1] MONTANA STATE UNIV,DEPT PHYS,BOZEMAN,MT 59717
关键词
ACCRETION; ACCRETION DISKS; GALAXIES; INDIVIDUAL; NGC; 7469; ARK; 120; SEYFERT; X-RAYS;
D O I
10.1093/mnras/265.4.996
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present spatial, temporal and spectral analyses of. ROSAT Position Sensitive Proportional Counter (PSPC) observations of the Seyfert 1 galaxies NGC 7469 and Ark 120. Both of these sources show evidence for excess emission and more complex 0.1-2.5 keV spectra than are predicted by simple extrapolations of higher energy power laws. We find that the spectrum of NGC 7469 can be explained by models that have secondary power-law, secondary bremsstrahlung, secondary blackbody or emission-line components. We find evidence for 0.1-2.5 keV intensity variability of NGC 7469. The spectrum of Ark 120 is better described by models with secondary continuum components than by models with sharper spectral features. We discuss the agreement between X-ray and ultraviolet observations of these sources and examine the observations in the context of accretion disc reflection models. The inner parts of discs are likely to be reflective below approximate to 0.24 keV, and this reflectivity complicates simple models of the soft excess.
引用
收藏
页码:996 / 1002
页数:7
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