A PRESTO-based Parallel Pulsar Search Pipeline And Pulsar Signal De-noising

Pulsar source is the end of the evolution,Pulsar is the product of supernova explosion and nuclear collapse,and is essentially a highly magnetized rotating neutron star.Pulsars have the characteristics of precise and regular period,small volume,high density and high speed rotation.The search and research of pulsars will contribute to the development of satellite navigation,astrophysics,particle physics and the exploration of the mysteries of the development of the universe.The 500 m Aperture Spherical Telescope(FAST)has the characteristics of the largest aperture and the most sensitive.It will make significant breakthroughs in the frontier areas such as pulsar search,international VLBI network joint measurement,neutral hydrogen patrol and extraterrestrial life search.In the progress of pulsar search,radio telescope equipment is becoming more and more perfect,and the amount of observation data is increasing dramatically.In the future,the amount of data will reach 1-1000 EB.So pulsar search must be accelerated,or try to improve the pulsar search process.Developed a pulsar search pipeline based on PulsaR Exploration and Search Toolkit(PRESTO),this pipeline simply runs dedispersion,Fast Fourier Transformation(FFT),and acceleration search in process-level parallel to shorten the processing time.The pipeline can highly shorten the processing time,Under the parallel strategy,this method can greatly reduce the processing time.This method is applied to the data of Parkes multibeam pulsar Survey(PMPS),and the search method of searching pulsar in parallel is tested in PMPS data and FAST drift scanning data.About 16% of PMPS data sets(8240 files)are processed in clusters and 410535 candidates are obtained.Finally,2238 excellent candidates were selected.Among them,there are 16 best candidates,which were re examined by Parkes in April 2018 and July 2019 respectively.Two proved to be new pulsars.New pulsars are also found in FAST drift scan data.Finally,192(177 seconds)or 216(166 seconds)is chosen as the processing number of FAST drift scanning pulsar search.The best case is to enable hyper threading and turbo boost.There are still some missing pulsars in this method,mainly because of the noise interference,the difficulty of FFT calculation for a long period,the missed selection of suspected signals in the screening stage and so on.In this paper,we try to use wavelet transform to remove the noise in the pulsar signal,and use wavelet decomposition and wavelet threshold method to remove the noise,so as to see the pulsar pulse waveform,which will help to find more pulsars.