XMM-Newton observation of the Seyfert 1 ESO 198-G24

We present the results from an XMM-Newton observation (January 24, 2001) of the bright Seyfert 1 galaxy ESO 198-G24 ( z=0.045). We found that this Seyfert has an intrinsic 2-10 keV luminosity of about 10 44 erg s -1. This source shows no intrinsic absorption in addition to the Galactic absorption ( ${\cal N}_{\rm H}\sim3\times10^{20}$ cm -2). We found both with EPIC and RGS that this source possesses significantly steeper spectra below ~1.5-2 keV than observed at higher X-ray energies, the so-called soft X-ray excess. The RGS spectra reveal no significant narrow absorption lines suggesting that if there is a warm absorber, it either has a relatively low column density, or a very high ionization parameter. The RGS data are well described by the combination of a power-law, a modified black body continuum, and weak relativistic lines of $\ion{O}{viii}$, and $\ion{C}{vi}$ Ly $_{\alpha}$. However other interpretations are not definitely excluded. The 2-10 keV energy band is well fitted by an absorbed power-law with a photon spectral index of $\Gamma=1.77\pm0.04$ (consistent with the typical $\Gamma \sim1.7$ found in Seyfert 1 galaxies). We found the presence of a narrow Gaussian emission line at 6.41 keV (i.e. < $\ion{Fe}{xvii}$) with a moderate equivalent width of about 60-70 eV, and we found an upper limit for a broad component, if any, of 75 eV. We also found a weak absorption edge associated with cold iron with an optical depth of about 0.2.

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