Flaring from the supermassive black hole in Mrk 335 studied withSwiftandNuSTAR

Abstract

Monitoring of the narrow line Seyfert 1 galaxy Markarian 335 (Mrk 335) with the Swift satellite discovered an X-ray flare beginning 2014 August 29. At the peak, the 0.5-5 keV count rate had increased from that in the low flux state by a factor of 10. A target of opportunity observation was triggered with NuSTAR, catching the decline of the flare on 2014 September 20. We present a joint analysis of Swift and NuSTAR observations to understand the cause of this flare. The X-ray spectrum shows an increase in directly observed continuum flux and the softening of the continuum spectrum to a photon index of 2.49 +0.08 −0.07 compared to the previous low flux observations. The X-ray spectrum remains well-described by the relativistically blurred reflection of the continuum from the accretion disc whose emissivity profile suggests that it is illuminated by a compact X-ray source, extending at most 5.2 r g over the disc. A very low reflection fraction of 0.41 +0.15 −0.15 is measured, unexpected for such a compact corona. The X-ray flare is, hence, interpreted as arising from the vertical collimation and ejection of the X-ray emitting corona at a mildly relativistic velocity, causing the continuum emission to be beamed away from the disc. As the flare subsides, the base of this jet-like structure collapses into a compact X-ray source that provides the majority of the radiation that illuminates the disc while continuum emission is still detected from energetic particles further out, maintaining the low reflection fraction.

The X-Ray Polarization of the Accretion Disk Coronae of Active Galactic Nuclei

“…The source harbors a supermassive BH with a mass of M = 2.6 × 10 7 M accreting at a rate ofṀ = 0.2Ṁ edd (Wilkins et al 2015). Fitting the NuSTAR energy spectrum gives a 2-10 keV photon index of Γ ≈ 1.9, and the fit of the Fe Kα line suggests a black hole spin of a = 0.89 in geometric units and a black hole inclination of ∼ 70…”

Normalizing a relativistic model of X-ray reflection

“…This energy range, which encompasses the peak of the Compton hump, is a good choice because the reflection spectrum is dominated there by Compton scattering and therefore depends weakly on the Fe abundance or ionization state of the reflector. We note that some authors use a similar definition, but employ a wider energy band (see, e.g., Wilkins et al 2015;Fürst et al 2015).…”

AGN Coronae through a Jet Perspective

“…Stochastic motions in the corona have been observed in individual AGN, including in Mrk 335 (Parker et al 2014;Wilkins et al 2015) and 1H 0707-495 (Fabian et al 2009, 2012Wilkins et al 2014). Through the use of detail modeling of the Fe Kα line, the reflection fraction is inversely correlated with flux (e.g., Zdziarski et al 1999;Parker et al 2014;Wilkins et al 2014Wilkins et al , 2015.…”