An extreme gravitationally redshifted iron line at 4.8 keV in Mrk 876

Abstract

X-ray spectral lines at unforeseen energies are important because they can shed light on the extreme physical conditions of the environment around the supermassive black holes of active galactic nuclei (AGN). Mrk 876 displays such a line at 4.8 keV rest-frame energy. A possible interpretation of its origin can be found in the hotspot scenario. In this scenario the primary radiation from a flare in the hot corona of an AGN illuminates a limited portion of the accretion disk that emits by fluorescence. In this context the line can represent an extreme gravitationally redshifted Fe line originating on the accretion disk below 6 gravitational radii from a rotating supermassive black hole. The correct estimate of the line significance requires a dedicated approach. Based on an existing rigorous approach, we have performed extensive Monte Carlo simulations. We determine that the line is a real feature at ~99 confidence level.

ApJL accepted

References in corpus (5)

• Fe K Emission and Absorption in the XMM-EPIC Spectrum of the Seyfert Galaxy IC 4329a
• Relativistic spectral features from X-ray illuminated spots and the measure of the black hole mass in AGN
• Modelling the spectral response of the Swift-XRT CCD camera: Experience learnt from in-flight calibration
• On the evidence for narrow, relativistically shifted X-ray lines
• Unveiling the broad band X-ray continuum and iron line complex in Mkr 841

Cited by in corpus (5)

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• Implications of Einstein-Maxwell dilaton-axion gravity from the black hole continuum spectrum
• Hard X-Ray broadband spectroscopy of Mrk 876: characterizing its spectrum
• Signatures of regular black holes from the quasar continuum spectrum
• Quasar continuum spectrum disfavors black holes with a magnetic monopole charge