Intrinsic Absorption in the Spectrum of Mrk 279: Simultaneous Chandra, FUSE, and STIS Observations

摘要

We present a study of the intrinsic X-ray and far-ultraviolet absorption inthe Seyfert 1.5 galaxy Markarian 279 using simultaneous observations from theChandra X-ray Observatory, the Space Telescope Imaging Spectrograph aboard theHubble Space Telescope, and the Far Ultraviolet Spectroscopic Explorer (FUSE).We also present FUSE observations made at three additional epochs. We detectthe Fe K-alpha emission line in the Chandra spectrum, and its flux isconsistent with the low X-ray continuum flux level of Mrk 279 at the time ofthe observation. Due to low signal-to-noise ratios in the Chandra spectrum, noO VII or O VIII absorption features are observable in the Chandra data, but theUV spectra reveal strong and complex absorption from HI and high-ionizationspecies such as O VI, N V, and C IV, as well as from low-ionization speciessuch as C III, N III, C II, and N II in some velocity components. The far-UVspectral coverage of the FUSE data provides information on high-order Lymanseries absorption, which we use to calculate the optical depths and line andcontinuum covering fractions in the intrinsic HI absorbing gas in aself-consistent fashion. The UV continuum flux of Mrk 279 decreases by a factorof ~7.5 over the time spanning these observations and we discuss theimplications of the response of the absorption features to this change. Fromarguments based on the velocities, profile shapes, covering fractions andvariability of the UV absorption, we conclude that some of the absorptioncomponents, particularly those showing prominent low-ionization lines, arelikely associated with the host galaxy of Mrk 279, and possibly with itsinteraction with a close companion galaxy, while the remainder arises in anuclear outflow.