Search for neutron star spin periods in X-ray bursts.

Abstract

We report a search for pulsations in 147 Type 1 X-ray bursts observed with EXOSAT in 10 X-ray burst sources. Instead of treating each burst separately, we incoherently averaged the power spectra of all of the bursts of a given burster to improve statistics. No periodicities were detected; 99% confidence upper limits on the modulation depths of possible periodic signals with frequencies between 1 and 2048 Hz range from 2 to 20% depending on source and frequency range.