Discovery of the Narrow-Line Seyfert 1 Galaxy Markarian 335 in a Historical Low X-Ray Flux State

Abstract

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)×10²³ 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.