SIMBAD references

2015MNRAS.447.1692Y - Mon. Not. R. Astron. Soc., 447, 1692-1704 (2015/February-3)

Correlation between the photon index and X-ray luminosity of black hole X-ray binaries and active galactic nuclei: observations and interpretation.

YANG Q.-X., XIE F.-G., YUAN F., ZDZIARSKI A.A., GIERLINSKI M., HO L.C. and YU Z.

Abstract (from CDS):

We investigate the observed correlation between the 2-10 keV X-ray luminosity (in unit of the Eddington luminosity; lX ≡ LX/LEdd) and the photon index (Γ) of the X-ray spectrum for both black hole X-ray binaries (BHBs) and active galactic nuclei (AGNs). We construct a large sample, with 10^- 9^ ≲ lX ≲ 10^- 1^. We find that Γ is positively and negatively correlated with lX when lX ≳ 10^- 3^ and 10^- 6.5^ ≲ lX ≲ 10^- 3^, respectively, while Γ is nearly a constant when lX ≲ 10^- 6.5^. We explain the above correlation in the framework of a coupled hot accretion flow-jet model. The radio emission always comes from the jet while the X-ray emission comes from the accretion flow and jet when lX is above and below 10–6.5, respectively. More specifically, we assume that with the increase of mass accretion rate, the hot accretion flow develops into a clumpy and further a disc-corona two-phase structure because of thermal instability. We argue that such kind of two-phase accretion flow can explain the observed positive correlation.

Abstract Copyright: © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society (2014)

Journal keyword(s): accretion, accretion discs - galaxies: active - quasars: general - X-rays: general - X-rays: binaries

Simbad objects: 17

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2021.06.16-03:20:22

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