XMM-Newton observations of the Narrow-Line Seyfert 1 galaxy Mrk 335 in an historical low X-ray flux state

TL;DR

This paper reports the discovery of strong soft X-ray emission lines and a complex continuum in the Seyfert galaxy Mrk 335 during its lowest observed X-ray flux state, revealing new spectral features and insights into its accretion environment.

Contribution

First detailed X-ray spectral analysis of Mrk 335 during an extreme low-flux state, identifying new emission lines and modeling the complex spectrum with partial covering and reflection models.

Findings

Detection of strong soft X-ray emission lines including highly ionized Fe, O VII, Ne IX, Mg XI.

Confirmation of a narrow Fe Kα line at 6.4 keV.

X-ray flux in this state is the lowest ever observed for Mrk 335.

Abstract

We report the discovery of strong soft X-ray emission lines and a hard continuum above 2 keV in the Narrow-Line Seyfert 1 galaxy Mrk 335 during an extremely low X-ray flux state. Mrk 335 was observed for 22 ks by XMM-Newton in July 2007 as a Target of Opportunity to examine it in its X-ray low-flux state, which was discovered with Swift. Long-term light curves suggest that this is the lowest flux state this AGN has ever been seen in. However, Mrk 335 is still sufficiently bright that its X-ray properties can be studied in detail. The X-ray continuum spectrum is very complex and requires several components to model. Statistically, partial covering and blurred reflection models work well. We confirm the presence of a strong narrow Fe line at 6.4 keV. High-resolution spectroscopy with the XMM-RGS reveals strong, soft X-ray emission lines not detected in previous, higher signal-to-noise, XMM-Newton observations, such as: highly ionized Fe lines, O VII, Ne IX and Mg XI lines. The optical/UV fluxes are similar to those previously measured with Swift. Optical spectroscopy taken in 2007 September do not show any changes to optical spectra obtained 8 years earlier.