X-ray reflection by photoionized accretion discs

By D. Ballantyne, R. Ross, A. C. F. IoA, Cambridge, College of the Holy Cross, Usa. 2001

148 citations recorded by the source corpus.

We present the results of reflection calculations that treat the relevant physics with a minimum of assumptions. The temperature and ionization structure of the top five Thomson depths of an illuminated disc are calculated while also demanding that the atmosphere is in hydrostatic equilibrium. In agreement with Nayakshin, Kazanas & Kallman, we find that there is a rapid transition from hot to cold material in the illuminated layer. However, the transition is usually not sharp so that often we find a small but finite region in Thomson depth where there is a stable temperature zone at T \sim 2 x 10^{6} K due to photoelectric heating from recombining ions. As a result, the reflection spectra often exhibit strong features from partially-ionized material, including helium-like Fe K lines and edges. We find that due to the highly ionized features in the spectra these models have difficulty correctly parameterizing the new reflection spectra. There is evidence for a spurious $R-\Gamma$ correlation in the ASCA energy range, where $R$ is the reflection fraction for a power-law continuum of index $\Gamma$, confirming the suggestion of Done & Nayakshin that at least part of the R-Gamma correlation reported by Zdziarski, Lubinski & Smith for Seyfert galaxies and X-ray binaries might be due to ionization effects. Although many of the reflection spectra show strong ionized features, these are not typically observed in most Seyfert and quasar X-ray spectra.

Subfields: Astronomy and Astrophysics, Statistics and Probability

View Paper: https://www.semanticscholar.org/paper/3cebb1891dfcc0a9216feafa935f7b49dfe275b0

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Citations in the corpus

A comprehensive range of X-ray ionized-reflection models (2005, background): “Furthermore, Ballantyne et al. (2001) found that models for reflection by atmospheres in hydrostatic equilibrium could befit by diluted versions of constant-density reflection models.”
X-RAY REFLECTED SPECTRA FROM ACCRETION DISK MODELS. III. A COMPLETE GRID OF IONIZED REFLECTION CALCULATIONS (2013, background): “…disk more accurately (Nayakshin et al. 2000), and that its reflected spectrum is in fact different from the one predicted by constant density models (see also Rozanska & Czerny 1996; Nayakshin & Kallman 2001; Ballantyne et al. 2001; Dumont et al. 2002; Ross & Fabian 2007; Różańska & Madej 2008).”
Do X-ray binary spectral state transition luminosities vary? (2003, background): “…the hard x-rays away from the accretion disk (Beloborodov 1999), a jet doing the same thing (Markoff et al. 2003), or as a result of ionization effects which cause an artifical correlation between reflection fraction and spectral shape to appear (Done & Nayakshin 2001; Ballantyne et al. 2001).”
X-RAY REFLECTED SPECTRA FROM ACCRETION DISK MODELS. I. CONSTANT DENSITY ATMOSPHERES (2010, result): “…et al. 1996; Matt et al. 1996; Poutanen et al. 1996; Blackman 1999; Ross & Fabian 2005), while hydrostatic calculations have been carried out by Rozanska & Czerny (1996); Nayakshin et al. (2000); Nayakshin & Kallman (2001); Ballantyne et al. (2001); Dumont et al. (2002) and Ross & Fabian (2007).”
Fluorescent iron lines as a probe of astrophysical black hole systems (2002, methodology): “When faced with real data, how is one to make progress given the complexities involved in modeling the reflection spectrum? A major simplification, pointed out by David Ballantyne and collaborators [181], is that self-consistent reflection spectra can be approximately mapped to more manageable const”