Akademik Veri Yönetim Sistemi
Sunum, ss.1, 2023
We present a detailed systematic pulse search for three Intermittent-Accreting Millisecond X-ray Pulsars (Intermittent-AMXPs), HETE J1900. 1-2455, SAX J1748. 9-2021, Aql X-1, via Z2 and maximum likelihood techniques by using 20 years data of Rossi X-ray Timing Explorer/Proportional Counter Array (RXTE/PCA) in the energy range of 3.0–30.0 KeV. We first performed pulse scan by using Z2 technique for every 25s time interval by shifting 1s in millisecond sensitivities to cover all observation data set around the detected frequency given in the literature. We tracked the Z2 power over time and flagged the time intervals exceeded defined threshold for each source as pulse candidates. We built the pulse profiles for the candidate segments and checked the amplitude of the pulses to better define pulsed regions. The pulse list throughout our scan has new discoveries while covering the pulsed regions presented in the literature for these three sources. For a deeper search, using the pulses obtained from Z2 method as probability density function as input parameter, we rescanned the duration covering around the obtained pulse by using maximum likelihood technique. We checked a systematic phase shift pattern over search duration. In conclusion, we discuss the advantages and disadvantages of the timing methods in millisecond rages as well as identifying new pulsed regions in intermittent-AMXPs.