A detailed analysis of the high resolution X-ray spectra of NGC 3516: Variability of the ionized absorbers

TL;DR

This study re-analyzed X-ray spectra of NGC 3516, revealing multiple ionized absorbers with variable properties, constraining their locations and physical states, and suggesting complex multi-phase outflows in the active galaxy.

Contribution

It provides a detailed analysis of ionized absorber variability and their spatial distribution in NGC 3516, with constraints on their physical conditions and origins.

Findings

Two absorber components respond to luminosity changes, indicating proximity to the central engine.

Three outflowing components are located beyond 10^{16-17} cm, with some possibly in pressure equilibrium.

No correlation between absorber covering factor changes and source flux, implying different variability mechanisms.

Abstract

We re-analyzed the 9 observations performed on 2006 by XMM-Newton and Chandra in the 0.3 to 10 keV energy band of NGC 3516 (Seyfert 1.5). The best fit model of these observations consists of a continuum emission absorbed by four ionized components and ten narrow emission lines. Three ionized absorbing components produce features in the soft X-ray band. The fourth ionization component produces FeXXV-XXVI in the hard- energy band. We study the absorbers time response to well detect changes in the X-ray luminosity of this source, only two components show clear opacity changes consistent with gas close to photoionization equilibrium. The other two components do not seem to respond to continuum variations. This response time allows us to constrain their location. One outflowing component must be located within the obscuring torus, at a distance 2.7X10^17 cm from the central engine, likely originated in the accretion disk. The three remaining outflowing components are at distances larger than 10^{16-17} cm. Two of them have similar outflow velocities and locations, these may be in pressure equilibrium, forming a multi-phase medium, if the gas has metallicity larger than the solar one (5 times). We find no correlation between the change in covering factor of the absorbers and the flux of the source. This, in connection with the observed variability of the ionized absorbers, suggests that the changes in flux are not produced by this material. If the variations are indeed produced by obscuring clumps of gas, these must be located much closer in to the central source.