XMM - Newton observations of the Seyfert 1 galaxy NGC 3227
Abstract
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 (Γ~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 (~6.5×1022 cm-2) larger than previously measured and covering a significant fraction (~ 90 %) of the central source. The soft X-ray continuum is also attenuated due to the presence of ionized material (ξ~50-90 erg s-1 cm) suggesting the presence of a substantial amount of gas (NH~2-91021 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.
- Publication:
-
Nuclear Physics B Proceedings Supplements
- Pub Date:
- June 2004
- DOI:
- 10.1016/j.nuclphysbps.2004.04.028
- Bibcode:
- 2004NuPhS.132..181G