| Abstract : | Pulsars are usually detected by their narrow pulses or periodicity in time domain data. With a synthesis imaging telescope like the GMRT, typically pulsar surveys use wider incoherent beams to map large areas of the sky, but the incoherent beam is less sensitive compared to regular imaging data. Also, the detection sensitivity of time-domain searches for pulsars is affected by dispersion smearing, scattering, and rapid orbital motion of pulsars in binaries. The radio continuum images do not suffer from the limitations of time domain searches. They, therefore, are equally sensitive to all pulsars and allow us to find hard-to-detect pulsars, such as sub-millisecond pulsars, pulsar-black hole systems, and pulsars near the Galactic Centre. Building on a variance imaging technique proposed by Dai et al (2016), we have developed a new technique that detects pulsar candidates in standard radio images by measuring their scintillation bandwidth and timescale from the autocorrelation of dynamic spectra of sources. We use existing GMRT observations of PSR B1508+55 and its neighbouring sources as a test case for our technique. We demonstrate that the technique correctly differentiates between the pulsar and other non-scintillating point sources and show that the extracted dynamical spectrum of the pulsar is equivalent to that extracted from the GMRT phased array beam. We are developing an automated pipeline for processing archival data and testing it on GMRT and uGMRT data. We will show results from our analysis of known pulsar fields and challenges in dealing with interference and instrumental effects. |
