An XMM-Newton observation of the Seyfert 2 galaxy NGC 6300.: I.: The nucleus

We present results from a half-day observation by XMM-Newton of the nucleus of the nearby Seyfert 2 galaxy NGC 6300. The X-ray spectrum of the nucleus consists of a heavily absorbed hard component dominating the 3-10 keV band and a soft component seen in the 0.2-2 keV band. In the hard band, the spectrum is well fitted by a power-law model with photon index of 1.83 +/- 0.08 attenuated by a Compton-thin absorber (N-H similar or equal to 2.2 x 10(23) cm(-2)). A narrow iron line is detected at 6.43(-0.02)(+0.01) keV with an equivalent width of similar to 150 eV; the line velocity width is marginally resolved to be sigmasimilar to 60 eV. The soft emission can be modeled as a power law and may be emission scattered by surrounding plasma. Rapid and high-amplitude variability is observed in the hard X-ray band, whereas both the iron line and the soft emission show no significant variability. It is suggested that the nucleus has experienced an overall long-term trend of decreasing hard X-ray intensity on a timescale of years. We discuss the origins of the spectral components.