Chandra and XMM-Newton view of the warm absorbing gas in Mrk 290

Abstract

We present a detailed analysis of the Chandra HETGS and XMM-Newton high resolution spectra of the bright Seyfert 1 galaxy, Mrk 290. The Chandra spectra reveal complex absorption features that can be best described by a combination of three ionized absorbers. The outflow velocities of these warm absorbers are about 450 km/s, consistent with the three absorption components found in a previous far UV study. The ionizing continuum of Mrk 290 fluctuated by a factor of 1.4 during Chandra observations on a time scale of 17 days. Thus, we put a lower limit on the distance from the ionizing source of 0.9 pc for the medium ionized absorber and an upper limit on distance of 2.5 pc for the lowest ionized absorber. The three ionization components lie on the stable branch of the thermal equilibrium curve, indicating that the torus is most likely the origin of warm absorbing gas in Mrk 290. During the XMM-Newton observation, the ionizing luminosity was 50% lower compared to the one in the Chandra observation. Neither the ionization parameter nor the column density of the two absorbing components varied significantly, compared to the results from Chandra observations. However, the outflow velocities of both components were 1260 km/s. We suggest that an entirely new warm absorber from the torus passed through our line of sight. Assuming the torus wind model, the estimated mass outflow rate is about 1 Solar mass per year.