Combined Analysis of X-Ray Spectra of NGC 3227

Abstract

Abstract The 1.5 Seyfert galaxy NGC 3227 has been observed by several X-ray missions. We carried out a combined analysis of the data obtained by more recent major observations of this source—two observations performed by XMM-Newton in 2000 and 2006 and six observations performed by Suzaku in 2008. A unified model, which is consistent with all eight of the observations by the two satellites with large intensity and spectral changes, was constructed. The model consists of a hard power law with the spectral index of ΓHard = 1.4–1.7, which is interpreted as the Comptonized emission from the corona above an accretion disk. In the high-flux states, an additional soft excess component dominates, which is consistent with a model with either a steeper power law with ΓSoft = 3.3–3.85 or the warm Comptonization component. These emissions from the central engine are absorbed by a partial covering material and warm absorbers. A reflection component and several emission lines are also present. We examined the relationship between the intrinsic luminosity and the absorbers’ physical parameters such as the column density, which suggests that the source expanded significantly during the bright states when the soft excess is greatly enhanced.