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X-ray emission from hot accretion flows

Published online by Cambridge University Press:  25 July 2014

Andrzej Niedźwiecki ,
Fu-Guo Xie  and
Agnieszka Stȩpnik
Andrzej Niedźwiecki
Affiliation:
Department of Astrophysics, University of Łódź, Pomorska 149/153, 90-236 Łódź, Poland email: [email protected]
Fu-Guo Xie
Affiliation:
Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, China email: [email protected]
Agnieszka Stȩpnik
Affiliation:
Department of Astrophysics, University of Łódź, Pomorska 149/153, 90-236 Łódź, Poland email: [email protected]
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Abstract

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Radiatively inefficient, hot accretion flows are widely considered as a relevant accretion mode in low-luminosity AGNs. We study spectral formation in such flows using a refined model with a fully general relativistic description of both the radiative (leptonic and hadronic) and hydrodynamic processes, as well as with an exact treatment of global Comptonization. We find that the X-ray spectral index–Eddington ratio anticorrelation as well as the cut-off energy measured in the best-studied objects favor accretion flows with rather strong magnetic field and with a weak direct heating of electrons. Furthermore, they require a much stronger source of seed photons than considered in previous studies. The nonthermal synchrotron radiation of relativistic electrons seems to be the most likely process capable of providing a sufficient flux of seed photons. Hadronic processes, which should occur due to basic properties of hot flows, provide an attractive explanation for the origin of such electrons.

Keywords

accretion disksgalaxies: activeX-rays: galaxies
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 9 , Symposium S304: Multiwavelength AGN Surveys and Studies , October 2013 , pp. 266 - 269
Copyright
Copyright © International Astronomical Union 2014 

References

Beckmann, V., et al. 2011 AA, 531, 70CrossRefGoogle Scholar
Brenneman, L., et al. 2012, ApJ, 744, 13Google Scholar
Donato, D., Sambruna, R. M., & Gliozzi, M. 2004 ApJ, 617, 915CrossRefGoogle Scholar
Emmanoulopoulos, D., et al. 2012, MNRAS, 424, 1327Google Scholar
Gu, M. & Cao, X. 2009, MNRAS, 399, 349CrossRefGoogle Scholar
Lubiński, P., et al. 2010, MNRAS, 408, 1851Google Scholar
Narayan, R. & McClintock, J. E. 2004, New Astron. Revs, 51, 733Google Scholar
Niedźwiecki, A., Xie, F.-G., & Stȩpnik, A. 2013, MNRAS, 432, 1576Google Scholar
Niedźwiecki, A., Xie, F. G., & Zdziarski, A. 2012, MNRAS, 420, 1195Google Scholar
Xie, F.-G., et al. 2010, MNRAS, 403, 170Google Scholar
Yamada, S., et al. 2009, PASJ, 61, 309CrossRefGoogle Scholar
Yang, , et al. 2009, ApJ, 691, 131Google Scholar
Yuan, F. & Zdziarski, A. 2004, MNRAS, 354, 953CrossRefGoogle Scholar
Zhou, X.-L. & Zhang, S.-N. 2010, ApJ (Letters), 713, L11Google Scholar