The Kinematics and Physical Conditions of the Ionized Gas in NGC 4593 fromChandraHigh‐Energy Grating Spectroscopy

We observed the Seyfert 1 galaxy NGC 4593 with the Chandra high energytransmission gratings and present a detailed analysis of the soft X-rayspectrum. We measure strong absorption lines from He-like O, Ne, Mg, Si, H-likeN, O, Ne, Mg, Si and highly ionized Fe XIX-XXV. Only the NLya, OLya and MgLyalines appear to be marginally resolved. We identify a spectral feature at $\sim0.707$ keV with a neutral Fe L edge, which might suggest that there is dustalong the line-of-sight to \ngc. Neutral Si absorption, which might also beexpected from absorption due to dust is present (though not significantly) inthe form of a weak neutral Si edge. We also detect, at marginal signficance,NLya and O VII (r) 1s-2p ($\lambda 21.602 $) absorption at $z \sim 0$, due to ahot medium in our Local Group. The soft X-ray spectrum of NGC 4593 isadequately described by a simple, single-zone photoionized absorber with anequivalent Hydrogen column density of $5.37^{+1.45}_{-0.79} \times 10^{21} \\rm{cm}^{-2}$ and an ionization parameter of $\log \xi= 2.52^{+0.06}_{-0.04}$ergs cm $\rm{s}^{-1}$ although there remain some features which are notidentified. Although the photoionized gas almost certainly is comprised ofmatter in more than one ionization state and may consist of several kinematiccomponents, data with better signal-to-noise ratio and better spectralresolution are required to justify a more complex model.Comment: ApJ accepted. 44 pages, 13 figs (5 colour). Abstract abridge