Fourier‐resolved spectroscopy of AGN using XMM‐Newton data

Abstract

We present a brief account of the theory on which the novel method of 'Fourier-resolved spectroscopy' is based. We summarize the results from the past application of this method to the study of Galactic Black Hole candidate sources and MCG-6-30-15, and we present new results from the Fourier-resolved spectroscopy of archival XMM-Newton data of five AGN, namely, Mrk 766, NGC 3516, NGC 3783, NGC 4051 and Ark 564. When we combine all the past and present results from Galactic sources and AGN, we find that the slope of the Fourier-resolved spectra in accreting black hole systems decreases with increasing frequency as ∝ f −0.25 , irrespective of whether the system is in its High or Low state. We find significant evidence that the iron line in Mrk 766, NGC 3783 and NGC 4051 is variable on time scales ∼ 1 day-1 hour. There is an indication that, just like in Galactic sources, the equivalent width of the line in the Fourier-resolved spectra of AGN decreases with increasing frequency.

Fourier‐Resolved Spectroscopy of 4U 1728‐34: New Insights into Spectral and Temporal Properties of Low‐Mass X‐Ray Binaries

“…This technique is known as Fourier Resolved Spectroscopy (FRS) (e.g. Revnivtsev et al 1999;Zycki 2003;Papadakis et al 2005Papadakis et al , 2006. In short, instead of producing the power spectra as a function of photon energy, as it is customary, this technique accumulates the variability amplitudes over several well defined frequency bands for each energy bin to produce the energy spectra of a source for the specific frequency bands considered.…”

“…It was pointed out that this method is particularly suited for the study of spectral features that result from X-ray reprocessing where the light crossing time provides a natural frequency filter; in this case FRS can provide straightforward insights about the geometry of the reprocessing medium. So far, this technique has been applied successfully to galactic black hole candidates (Revnivtsev et al 1999;Gilfanov et al 2001;Sobolewska & Zycki 2006;Reig et al 2006), to neutron-star LMXBs (Gilfanov & Revnivtsev et al 2005) and also to AGN (Papadakis et al 2005(Papadakis et al , 2006 yielding insights into variability of different spectral components and infer their spatial arrangements.…”

Frequency-resolved spectroscopy of XB 1323−619 using XMM-Newton data: detection of a reflection region in the disc

“…FRS technique is applied to Galactic black hole candidates (Revnivtsev et al 1999; Gilfanov et al 2003; Reig et al 2006; Sobolewska & Zycki 2006) to neutron star LMXBs (Gilfanov & Revnivtsev 2005; Renvivtsev & Gilfanov 2006; Shrader, Reig & Kazanas 2007) and also to active galactic nuclei (Papadakis, Kazanas & Ayklas 2005; Papadakis, Ioannou & Kazanas 2006). The systematic application of this technique to Z sources in several different states of the sources yields soft and hard variable thermal components.…”