Variation of the broad X-ray iron line in MCG-6-30-15 during a flare

Abstract

We report results on the broad iron emission line of the Seyfert galaxy MCG-6-30-15, obtained from the second long ASCA observation in 1997. The time-averaged profile of the broad line is very similar to that seen with ASCA in 1994, so confirming the detailed model fit then obtained. A bright flare is seen in the light curve, during which the continuum was soft. At that time the emission line peaks around 5 keV and most of its emission is shifted below 6 keV with no component detected at 6.4 keV (EW<60 eV). This can be interpreted as the result of an extraordinarily large gravitational redshift due to a dominant flare occurring very close to the black hole at a radius of <5m.Comment: 5 pages, accepted or publication in MNRAS Letter

A long, hard look at MCG–6-30-15 with XMM-Newton

“…• Previous observations with ASCA ( [2,3,21]) and RXTE ( [22,23]) showed the photon index of the 2 − 10 keV continuum to be correlated with EPIC pn difference spectrum produced by subtracting the low flux spectrum from the high flux spectrum, shown as a ratio to a power-law (modified by Galactic absorption) fitted across the 3 − 10 keV range. The difference spectrum is consistent with a power-law component (PLC) modified by warm absorption.…”

“…MCG-6-30-15 has received particular attention since ASCA observations revealed the presence of a broad, asymmetric emission feature between 4 − 7 keV, identified with a highly broadened Fe Kα emission line ( [1,2,3]). The line profile can be explained in terms of fluorescent emission from an accretion disc extending down to ∼ < 6 r g about a black hole ( r g ≡ GM/c 2 ).…”

Atomic X-ray spectroscopy of accreting black holes

“…A dramatic example of a red-shifted iron Kα line profile has been documented for the Seyfert 1 galaxy MCG-6-30-15 [161] [162], in which the line profile was observed to vary dramatically, from a profile for which the emission appeared to be dominated by large radii, and then to a profile in which the bulk of the emission was observed to lie below the rest energy. This latter result implies that the emission originated from r < 6M , which, given the assumption that radiation from within the ISCO is unobservable, implies black hole spin.…”

A Relativistic F[CLC]e[/CLC] Kα Emission Line in the Intermediate-Luminosity [ITAL]B[CLC]eppo[/CLC]SAX[/ITAL] Spectrum of the Galactic Microquasar V4641 Sgr

“…Following Iwasawa et al (1999), the ratio is formed by ignoring the 4-7 keV range when fitting the spectra. It is apparent that the line may not be intrinsically narrow-the profile revealed in the data/model ratio is similar to those expected for a line produced by irradiation of the inner accretion disk around a black hole (Fabian et al 1989;Laor 1991).…”