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 detected a very strong X-ray decline in the galaxy IRAS23226-3843 withinthe XMM-Newton slew survey in 2017. Subsequently, we carried out multi-bandfollow-up studies to investigate this fading galaxy in more detail. We tookdeep follow-up Swift, XMM-Newton, and NuSTAR observations in combination withoptical SALT spectra of IRAS23226-3843 in 2017. In addition, we reinspectedoptical, UV, and X-ray data that were taken in the past. IRAS23226-3843decreased in X-rays by a factor of more than 30 with respect to ROSAT and Swiftdata taken 10 to 27 years before. The broadband XMM-Newton/NuSTAR spectrum ispower-law dominated, with a contribution from photoionized emission from coldgas, likely the outer accretion disk or torus. The optical continuum decreasedby 60 percent and the Balmer line intensities decreased by 50 percent between1999 and 2017. The optical Seyfert spectral type changed simultaneously withthe X-ray flux from a clear broad-line Seyfert 1 type in 1999 to a Seyfert 1.9type in 2017. The Balmer line profiles in IRAS23226-3843 are extremely broad.The profiles during the minimum state indicate that they originate in anaccretion disk. The unusual flat Balmer decrement Ha/Hb with a value of 2indicates a very high hydrogen density of n_(H) > 10 exp(11) cm^(-3) at thecenter of the accretion disk. IRAS23226-3843 shows unusually strong FeII blendswith respect to the broad line widths, in contrast to what is known fromEigenvector 1 studies.

Optical and X-ray discovery of the changing-look AGN IRAS23226-3843 showing extremely broad and double-peaked Balmer profiles