出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：GRO J1655-40 showed renewed X-ray activity in late February, 2005. We study the spectral
properties and the Quasi-Periodic Oscillations (QPO) properties of this object for the first two
weeks of RXTE observations after the outburst started. We show that as the spectrum becomes
softer with time, the QPO frequency goes up. We analysed the QPOs for the period 25th Feb.
2005 to 12th of March, 2005 and showed that the frequency of QPO increased monotonically
from 0:082Hz to 15:01Hz. This agrees well if the oscillating shock is assumed to propagate with
a constant velocity of about 1:9km s1s.
