The collisional and photoionized plasma in the polarized NLS1 galaxy Mrk 1239

Abstract

ABSTRACTMrk 1239 is a highly polarized NLS1 in the optical band, whose 0.3–3 keV spectrum has remained remarkably consistent over more than two decades of observation. Previous analysis of this object suggested that the soft X-ray band was dominated by emission lines (collisionally and/or photoionized) from the distant host galaxy as the X-ray emission from the central engine was highly obscured. New XMM–Newton data of Mrk 1239 are presented here to investigate the soft X-ray band of this galaxy with high resolution. The first RGS spectra of this source reveal a plethora of ionized emission lines originating from two distinct plasmas, one collisionally ionized and the other photoionized at approximately equal brightness. The best-fitting model uses apec and xstar grids to account for the collisionally ionized and photoionized components, respectively. The fit improves significantly if the photoionized material is allowed to outflow at ≈500 km s−1, matching the outflow velocity of the forbidden O vii emission line. From constraints on the ionization and density of the photoionized material, we can estimate the location of it to be no further than a few pc from the central source, around the outer radius of the torus, which is consistent with the O vii(f) emission line. Properties of the collisionally ionized plasma are consistent with star formation rate (SFR) of $\approx 3 \hbox{$\rm \, M_{\odot }$}\textrm {yr}^{-1}$, which is comparable with several previous measurements of the SFR in this galaxy.