Evidence for a compact jet dominating the broadband spectrum of the black hole accretor XTE J1550-564 - Astrophysics > High Energy Astrophysical PhenomenaReportar como inadecuado




Evidence for a compact jet dominating the broadband spectrum of the black hole accretor XTE J1550-564 - Astrophysics > High Energy Astrophysical Phenomena - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: abridged The black hole X-ray binary XTE J1550-564 was monitoredextensively at X-ray, optical and infrared wavelengths throughout its outburstin 2000. We show that it is possible to separate the optical-near-infraredOIR jet emission from the OIR disc emission. Focussing on the jet component,we find that as the source fades in the X-ray hard state, the OIR jet emissionhas a spectral index consistent with optically thin synchrotron emission alpha~ -0.6 to -0.7, where F nu \propto nu^alpha. This jet emission is tightly andlinearly correlated with the X-ray flux; L OIR,jet \propto L X^0.98 +- 0.08suggesting a common origin. This is supported by the OIR, X-ray and OIR toX-ray spectral indices being consistent with a single power law alpha =-0.73. Ostensibly the compact, synchrotron jet could therefore account for ~100 % of the X-ray flux at low luminosities in the hard state. At the sametime, i an excess is seen over the power law decay of the X-ray flux at thepoint in which the jet would start to dominate, ii the X-ray spectrumslightly softens, which seems to be due to a high energy cut-off or breakshifting to a lower energy, and iii the X-ray rms variability increases. Thismay be the strongest evidence to date of synchrotron emission from the compact,steady jet dominating the X-ray flux of an X-ray binary. For XTE J1550-564,this is likely to occur within the luminosity range ~ 2 e-4 - 2 e-3 L Edd onthe hard state decline of this outburst. However, on the hard state rise of theoutburst and initially on the hard state decline, the synchrotron jet can onlyprovide a small fraction ~ a few per cent of the X-ray flux. Both thermalComptonization and the synchrotron jet can therefore produce the hard X-raypower law in accreting black holes.



Autor: D. M. Russell 1, D. Maitra 1,2, R. J. H. Dunn 3, S. Markoff 1 1 University of Amsterdam 2 University of Michigan 3 Excellence Clu

Fuente: https://arxiv.org/







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