XMM-Newton observations of the Seyfert 1 galaxy NGC 3227

被引:29
作者
Gondoin, P [1 ]
Orr, A [1 ]
Lumb, D [1 ]
Siddiqui, H [1 ]
机构
[1] European Space Agcy, Res & Sci Support Dept, NL-2200 AG Noordwijk, Netherlands
来源
ASTRONOMY & ASTROPHYSICS | 2003年 / 397卷 / 03期
关键词
galaxies : individual : NGC 3227; galaxies : nuclei; galaxies : Seyfert;
D O I
10.1051/0004-6361:20021574
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We report on an XMM-Newton observation of the Seyfert 1 galaxy NGC 3227 performed in November 2000. The observed X-ray spectrum above 4 keV is well fitted by a hard power law continuum (Gamma approximate to 1.5) and an absorption edge at 7.6 keV. An Fe K emission line with an equivalent width of 213 eV is detected at 6.4 keV. The line is narrow suggesting contribution from material in low ionization states (<Fe XVII) relatively far from a central black hole. The continuum is strongly absorbed at soft energies by a column of neutral gas (approximate to 6.5 x 10(22) cm(-2)) larger than previously measured and covering a significant fraction (approximate to 90%) of the central source. The soft X-ray continuum is also attenuated due to the presence of ionized material (xi approximate to 50-90 erg s(-1) cm) suggesting the presence of a substantial amount of gas (N-H approximate to 2-9 x 10(21) cm(-2)) in the vicinity (<0.4 pc) of the nucleus. We find that NGC 3227 exhibits significant spectral variability above 2 keV on time scales of a few ksec during the XMM-Newton observations. This short term variability is likely related to variation in the continuum emission. Comparisons with previous observations indicate that variability on timescale of a month also involves a change in the column densities of neutral absorbing material along the line of sight to the nucleus.
引用
收藏
页码:883 / 890
页数:8
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