Skip to main content

Research Repository

Advanced Search

A rapid occultation event in NGC 3227

A rapid occultation event in NGC 3227 Thumbnail


Abstract

NGC 3227 exhibits rapid flux and spectral variability in the X-ray band. To understand this behaviour, we conducted a coordinated observing campaign using 320 ks of XMM–Newton exposures together with 160 ks of overlapping NuSTAR observations, spanning a month. Here, we present a rapid variability event that occurs toward the end of the campaign. The spectral hardening event is accompanied by a change in the depth of an unresolved transition array (UTA), whose time-dependent behaviour is resolved using the RGS data. This UTA fingerprint allows us to identify this as a transit event, where a clump of gas having NH~5×1022atomscm-2?, log ? ~ 2 occults ~60 per cent of the continuum photons over the course of approximately a day. This occulting gas is likely associated with clouds in the inner broad-line region. An additional zone of gas with lower column and higher ionization, matches the outflow velocity of the variable zone, and may represent transmission through the cloud limb.

Acceptance Date Sep 3, 2018
Publication Date Dec 1, 2018
Publicly Available Date Mar 28, 2024
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Publisher Oxford University Press
Pages 2470 -2478
DOI https://doi.org/10.1093/mnras/sty2447
Keywords galaxies, active, individual, NGC 3227, Seyfert, X-rays
Publisher URL http://dx.doi.org/10.1093/mnras/sty2447

Files




Downloadable Citations