JournalThe extended emission line region of the Seyfert galaxy

We present the results of observations of the extended emission-line region of the Seyfert 2 galaxy Mrk 573, obtained using the WFPC2 camera on board HST and the TIGER integral eld spectrograph on the Canada France Hawaii Telescope. The WFPC2 observations consist of a set of narrow-band linear ramp lter images in the O iii]5007 and H + N ii]6583 lines, as well as continuum and other emission-line images obtained from the HST archive. The TIGER 3D (x,y,) data cubes cover the wavelength regions 5000/400 A (central wavelength/range of wavelength), including H and O iii]4959,5007, and 6750/400 A including H, N ii]6548,6583 and S ii]6717,6731. We describe and use a new deconvolution technique in which the spatial resolution of the TIGER data cubes is improved by using the higher resolution HST images in the same emission-lines, in combination with a standard Richardson-Lucy deconvolution. This`guided' deconvolution allows us to obtain the O iii] gaseous kinematics with unprecedented spatial resolution of 0: 00 35. The HST images outline the detailed complex structure of the central 3 kpc of this galaxy in the O iii] and H++N ii] lines, with strings of knots and a system of arcs straddling the nucleus. The O iii]/(H++N ii]) line ratio map shows that, taken together, all these individual features deene a double wedge form with sharp edges, consistent with an ionization cone. The { 2 { `linear' radio structure is closely associated with the strings of emission-line knots, with the northwest radio lobe lying inside one of the arcs. Strong velocity perturbations are found in the vicinity of all of the radio components, witnessing the interaction between the radio ejecta and the ambient material. The spectral and kinematical properties of the diierent components of the emission-line region of Mrk 573 are discussed in terms of various models of the interaction between the ejecta and the ambient gas. The emission-line knots, associated with the radio knots and the velocity perturbations, probably trace the deeection of the radio jet by clouds. The inner arcs, 1: 00 8 (570 pc) and 2: 00 3 (720 pc) from the nucleus, may represent radiative bow shocks driven by the radio jets. The similar structure of each of these arcs in the diierent emission lines, and the absence of any strong kinematic perturbation at the arcs themselves, indicate that they are not`photoionizing shocks', in which the gas is ionized by radiation from …