2007/09/07 by D. Grupe, Dirk Grupe, Stefanie Komossa +2
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/523042
ApJ Letter accepted; 8 pages, 2 figures; The new version has three more sentences in the introduction and three references added to the discussion
arxiv created 2007/09/07 · openalex publication_date 2007/10/02 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We report the discovery of the narrow-line Seyfert 1 galaxy Mrk 335 in an extremely low X-ray state. A comparison of Swift observations obtained in 2007 May and June/July with all previous X-ray observations between 1971 and 2006 show the AGN to have diminished in flux by a factor of more than 30, the lowest X-ray flux Mrk 335 has ever been observed in. The Swift observations show an extremely hard X-ray spectrum at energies above 2 keV. Possible interpretations include partial-covering absorption or X-ray reflection from the disk. In this Letter we consider the partial-covering interpretation. The Swift observations can be well fit by a strong partial-covering absorber with varying absorption column density [ N H = (1-4) × 10 23 cm -2 ] and a covering fraction f c = 0.9-1. When corrected for intrinsic absorption, the X-ray flux of Mrk 335 varies by only factors of 4-6. In the UV Mrk 335 shows variability on the order of 0.2 mag. We discuss the similarity of Mrk 335 to the highly variable NLS1 WPVS 007, and speculate about a possible link between NLS1 galaxies and broad-absorption-line quasars.