Timing Analysis Of Type ? X-ray Burst

Type ? X ray burst is an observational phenomenon in the light curve of neutron star low-mass X-ray binaries,and it occurs in relation to the hard surfaces of neutron stars.I study the timing properties of type ? X-ray bursts by the fast Fourier transform or Zn2 statistical to find X-ray burst oscillation which is the coherent signals in the X ray burst.They are important to probe the dense matter equation of state and the effects of strong gravity,to study the high magnetic field environment on the neutron star surface.In recent years,about 30 neutron star low-mass X-ray binaries have been detected X-ray burst oscillations from RXTE,Swift and NICER observations.The studies of Xray burst oscillations are also crucial to understand the spin up process of neutron star low-mass X-ray binaries through accretion and the evolution into millisecond pulsars.The different characteristics of burst oscillation signals between persistent accretionpowered pulsars,intermittent accretion-powered pulsars and sources without detectable accretion-powered pulsations can help us to study more about it.Swift is a NASA mission with international participation,we mainly process the low-energy band data of source of the neutron star ? X-ray burst from the Swift/BAT telescope.For the source that has been found burst oscillation,perform a search of Zn2 statistics near the previously searched oscillation frequency,the confidence of the oscillation signals on Swift/BAT was obtained to further confirm the authenticity of the frequency of the oscillation signals.The dynamic power spectrum of the edge with high confidence was drawn,and it was found that these oscillation signals mostly appeared at the tail of the burst,which was in line with the observed characteristics of the previous burst oscillation signals.When search the burst oscillation from the source that oscillation frequency unknown,according to the power density spectrum,the suspected oscillation signals were obtained and the confidence of the oscillation signals was estimated.The confidence of most of the oscillation signals searched were more than 99%.According to the dynamic power spectrum drawn,it was suspected that these oscillation-like signals appeared in the rising or falling stage of the burst.In the last part of this paper,we summarize the above work and look forward to the further research of type ? X-ray bursts.