Warm absorbers in X-rays (WAX), a comprehensive high-resolution grating spectral study of a sample of Seyfert Galaxies – II. Warm absorber dynamics and feedback to galaxies

Abstract

This paper is a sequel to the extensive study of warm absorber (WA) in X-rays carried out using high resolution grating spectral data from XMM-Newton satellite (WAX-I). Here we discuss the global dynamical properties as well as the energetics of the WA components detected in the WAX sample. The slope of WA density profile ($n\propto r^{-\alpha}$) estimated from the linear regression slope of ionization parameter $\xi$ and column density $N_H$ in the WAX sample is $\alpha=1.236\pm 0.034$. We find that the WA clouds possibly originate as a result of photo-ionised evaporation from the inner edge of the torus (torus wind). They can also originate in the cooling front of the shock generated by faster accretion disk outflows, the ultra-fast outflows (UFO), impinging onto the interstellar medium or the torus. The acceleration mechanism for the WA is complex and neither radiatively driven wind nor MHD driven wind scenario alone can describe the outflow acceleration. However, we find that radiative forces play a significant role in accelerating the WA through the soft X-ray absorption lines, and also with dust opacity. Given the large uncertainties in the distance and volume filling factor estimates of the WA, we conclude that the kinetic luminosity $\dot{E}_k$ of WA may sometimes be large enough to yield significant feedback to the host galaxy. We find that the lowest ionisation states carry the maximum mass outflow, and the sources with higher Fe M UTA absorption ($15-17\rm \AA$) have more mass outflow rates.