English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present results from a homogeneous analysis of the broadband 0.3-10 keVCCD resolution as well as of soft X-ray high-resolution grating spectra of ahard X-ray flux-limited sample of 26 Seyfert galaxies observed with XMM-Newton.Our goal is to characterise the warm absorber (WA) properties along theline-of-sight to the active nucleus. We significantly detect WAs in $65\%$ ofthe sample sources. Our results are consistent with WAs being present in atleast half of the Seyfert galaxies in the nearby Universe, in agreement withprevious estimates . We find a gap in the distribution of the ionisationparameter in the range $0.5<\log\xi<1.5$ which we interpret as a thermallyunstable region for WA clouds. This may indicate that the warm absorber flow isprobably constituted by a clumpy distribution of discrete clouds rather than acontinuous medium. The distribution of the WA column densities for the sourceswith broad Fe K$\alpha$ lines are similar to those sources which do not havebroadened emission lines. Therefore the detected broad Fe K$\alpha$ emissionlines are bonafide and not artifacts of ionised absorption in the soft X-rays.The WA parameters show no correlation among themselves, with the exception ofthe ionisation parameter versus column density. The shallow slope of the$\log\xi$ versus $\log v_{\rm out}$ linear regression ($0.12\pm 0.03$) isinconsistent with the scaling laws predicted by radiation ormagneto-hydrodynamic-driven winds. Our results suggest also that WA and UltraFast Outflows (UFOs) do not represent extreme manifestation of the sameastrophysical system.

monthly notices of the royal astronomical society

Warm absorbers in X-rays (WAX), a comprehensive high resolution grating  spectral study of a sample of Seyfert galaxies: I. A global view and  frequency of occurrence of warm absorbers