Search for pulsations in the LMXB EXO 0748-676

Abstract

We present here results from our search for X-ray pulsations of the neutron star in the low mass X-ray binary EXO 0748-676 at a frequency near the burst-oscillation frequency of 44.7 Hz. Using the observations made with the Proportional Counter Array onboard the Rossi X-ray Timing Explorer, we did not find any pulsations in the frequency band of 44.4 Hz to 45.0 Hz and obtained a 3σ upper limit of 0.47% on the pulsed fraction for any possible underlying pulsation in this frequency band. We also discuss the importance of EXO 0748-676 as a promising source for the detection of Gravitational Waves. © 2011 National Astronomical Observatories of Chinese Academy of Sciences and IOP Publishing Ltd.