ROSAT monitoring of persistent giant and rapid variability in the narrow-line Seyfert 1 galaxy IRAS 13224-3809

Th Boller, W. N. Brandt, A. C. Fabian, H. H. Fink

Research output: Contribution to journalArticle

122 Scopus citations

Abstract

We report evidence for persistent giant and rapid X-ray variability in the radio-quiet, ultrasoft, strong Fe II, narrow-line Seyfert 1 galaxy IRAS 13224-3809. Within a 30-d ROSAT High Resolution Imager (HRI) monitoring observation at least five giant-amplitude count rate variations are visible, with the maximum observed amplitude of variability being about a factor of 60. We detect a rise by a factor of about 57 in just 2 d. IRAS 13224-3809 appears to be the most X-ray-variable Seyfert known, and its variability is probably non-linear. We carefully check the identification of the highly variable X-ray source with the distant galaxy, and it appears to be secure. We examine possible explanations for the giant variability. Unusually strong relativistic effects and partial covering by occulting structures on an accretion disc can provide plausible explanations of the X-ray data, and we explore these two scenarios. Relativistic boosting effects may be relevant to understanding the strong X-ray variability of some steep-spectrum Seyferts more generally.

Original languageEnglish (US)
Pages (from-to)393-405
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume289
Issue number2
DOIs
StatePublished - Jan 1 1997

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint Dive into the research topics of 'ROSAT monitoring of persistent giant and rapid variability in the narrow-line Seyfert 1 galaxy IRAS 13224-3809'. Together they form a unique fingerprint.

  • Cite this