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

Abstract

Mrk 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.