Fe KαLine in Hard X-ray Emitting Symbiotic Stars

Abstract

The 6.4 keV iron emission line is typically created by irradiation of the neutral (or low ionized) iron by a hard X-ray source. Whereas the 6.7 and 7.0 keV emission lines are mainly produced by photoionization and collisional excitation in hot plasma, the 6.4 keV fluorescence line is typically a signature of either reflection from an accretion disk or absorption. We have surveyed the emission using a collection of Suzaku ob- servations of hard X-ray emitting symbiotic stars to better understand the geometry of these systems. We find that they do not seem to have a single geometry, and that while absorption-induced fluorescence leads to some emission in three of the hard X-ray emitting symbiotic stars (hSSs) in our study, CH Cyg, T CrB and RT Cru there are strong hints that significant 6.4 keV emission arises in the accretion disk irradiated by the hard X-rays from the boundary layer between the accretion disk and hot white dwarf in one of our sources, SS73 17. The 6.7 and 7.0 keV lines, however, are largely produced by collisional excitation in the vicinity of the compact white dwarf.

6 pages, 4 figures, Accepted for Publication in MNRAS

References in corpus (3)

• An XMM-Newton survey of broad iron lines in Seyfert galaxies
• The Nature of the Hard-X-Ray Emitting Symbiotic Star RT Cru
• Average Fe K-alpha emission from distant AGN

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• Peering into the central region of a nano-quasar: XMM-Newton and Chandra views of the CH Cyg Symbiotic System
• Gas phase SiO in the circumstellar environment of the recurrent nova T Coronae Borealis
• Long-term X-ray Variability of the Symbiotic System RT Cru based on Chandra Spectroscopy
• RT Cru: a look into the X-ray emission of a peculiar symbiotic star
• IGR J17463-2854, a Possible Symbiotic Binary System in the Galactic Center Region
• An XMM-Newton view of the Symbiotic Stars HM Sge, NQ Gem, and PU Vul
• X-ray Variability in the Symbiotic Binary RT Cru: Principal Component Analysis
• Near-Infrared Spectroscopy of Faint Discrete X-ray Point Sources Constituting the Galactic Ridge X-ray Emission
• A novel approach to detect line emission under high background in high-resolution X-ray spectra
• XMM-Newton and NuSTAR discovery of a likely IP candidate XMMU J173029.8-330920 in the Galactic Disk
• XMM-Newton follow-up of two eROSITA X-ray binary candidates
• X-ray luminous late-type giants: an overlooked population contributing to the Galactic ridge iron line emission