出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We have analyzed the 171 RXTE data sets of the black hole candidate GX 339-4 in the low/hard
state during its 1996.2005 outburst. All the broadband spectra were successfully modeled by a
simple analytic model, power-law with an exponential cutoff. The obtained energy cutoff(Ecut)
is distributed over 50.300 keV, and the photon index over 1.4.1.6. We found a clear correlation
(Ecut is proportional to L0:750:04) between luminosity in 2.200 keV (L) and Ecut when L is larger
than 51037 erg s1, while Ecut is almost constant at 200 keV when L is smaller than 51037
erg s1. This anti-correlation is unchanged by adopting the more physical model of thermal
Comptonization by Sunyaev and Titarchuk, although a slightly different relation is obtained as
the electron temperature is proportional to L0:230:02. These anti-correlations are qualitatively
explained by a picture where the energy ow rate from protons to electrons balance with cooling
due to inverse Compton scattering.
