Abstract Details

Name: Shubham Singh
Affiliation: National Centre For Radio Astrophysics
Conference ID: ASI2021_115
Title : Searching for Long Period Pulsars in data from the GHRSS Survey
Authors and Co-Authors : Shubham Singh(NCRA-TIFR), Jayanta Roy(NCRA-TIFR), Ujjwal Panda(BITS Pilani), Bhaswati Bhattacharya (NCRA-TIFR), B.W. Stappers(University of Manchester)
Abstract Type : Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : Despite five decades of pulsar searches, the fraction of long-period pulsars is very small in the current population. Only ∼8% of all pulsars discovered till date have periods longer than 2 seconds. This could be due to selection biases that are inherent in our current search paradigms, which are based on the conventional frequency-domain searches using Fast Fourier Transform (FFT). The Discovery of new long-period pulsars will populate the pulsar period versus period derivative diagram putting additional constraints on the theoretical death-line, a line predicted by pulsar emission models where radio emission is expected to cease. For example, ultra-slow pulsars PSR J2144-3933, with a period of 8.5 seconds, and PSR 0250+5854 with a period of 23 seconds are situated very near to the death line, restricting the pulsar death line. In addition, investigation of single-pulse properties such as sub-pulse drifting and nulling of the relatively long period pulsars are particularly useful to constrain pulsar emission models. Ongoing pulsar surveys (e.g. PALFA, SUPERB) have implemented a time-domain approach based on the Fast Folding Algorithm (FFA) to enhance the detection significance of pulsars with relatively higher periodicities. We have implemented this approach on the ongoing GMRT High-Resolution Southern Sky (GHRSS) survey, which is an off-Galactic plane survey at 300-500 MHz. This survey resulted in the discovery of 24 pulsars, out of which only 2 are slower than a second. We are now reprocessing ∼4000 square-degree archival GHRSS data, along with new data that is coming in from ongoing observations. I will present a comparison of the two techniques (FFT and FFA) over a range of parameters such as period, duty-cycle, profile shape as well as the instrumental red-noise contribution. The results (including new discoveries) from the FFA search of GHRSS survey data will also be reported.