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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Cen A hosts the closest active galactic nucleus to the Milky Way, which makesit an ideal target for investigating the dynamical processes in the vicinity ofaccreting supermassive black holes. In this paper, we present 14 Chandra HETGSspectra of the nucleus of Cen A that were observed throughout 2022. We comparedthem with each other, and contrasted them against the two previous ChandraHETGS spectra from 2001. This enabled an investigation into the spectralchanges occurring on timescales of months and 21 years. All Chandra spectracould be well fitted by an absorbed power law with a strong and narrow FeK$\alpha$ line, a leaked power law feature at low energies, and Si and SK$\alpha$ lines that could not be associated with the central engine. The fluxof the continuum varied by a factor of $2.74\pm0.05$ over the course of theobservations, whereas the Fe line only varied by $18.8\pm8.8\%$. The photonindex increased over 21 years, and the Hydrogen column density variedsignificantly within a few months as well. The Fe K$\alpha$ line was found at alower energy than expected from the Cen A redshift, amounting to an excessvelocity of $326^{+84}_{-94}~\mathrm{km}~\mathrm{s}^{-1}$ relative to Cen A. Weinvestigated warped accretion disks, bulk motion, and outflows as possibleexplanations of this shift. The spectra also featured ionized absorption linesfrom Fe XXV and Fe XXVI, describing a variable inflow.

Redshifted iron emission and absorption lines in the Chandra X-ray spectrum of Centaurus A