Abstract Details

Name: Parul Janagal
Affiliation: Indian Institute of Technology Indore
Conference ID: ASI2021_500
Title : Wide-band studies of the sub-pulse drifting phenomenon in PSR J1822-2256
Authors and Co-Authors : Parul Janagal(IIT Indore), Manoneeta Chakraborty(IIT Indore), Bhaswati Bhattacharyya(NCRA-TIFR), Ramesh Bhat(Curtin University), Sammy McSweeney(Curtin University)
Abstract Type : Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : Pulsars are nature’s premier laboratories for extreme physics, e.g., physics under extremely high gravitational and magnetic fields. Their emission mechanism is still an outstanding problem. The phenomenon of sub-pulse drifting, whereby systematic shifts are observed in the pulse phases of substructures within the main pulse(i.e., subpulses) and nulling(where pulsar emission temporarily ceases), can potentially provide an important key for unlocking the mystery of how pulsars work. Intending to investigate the underlying emission physics, we have undertaken phased-array observations of a number of pulsars that exhibit sub-pulse drifting, simultaneously covering the 300-500 MHz and 550-750 MHz frequency bands using the upgraded Giant Metrewave Radio Telescope (uGMRT). Our observations and analysis thus exploit the GMRT's high sensitivity, wide bandwidths, and sub-array capabilities. Three of the pulsars (PSR J1543+0929, PSR J1820-0427, and PSR J1834-0426) were also observed commensally with the Murchison Widefield Array that operates at frequencies below 300 MHz, thus providing simultaneous frequency coverage from 170 MHz to 750 MHz. I will present new results emerging from the wide-band investigation of single-pulse properties of a bunch of pulsars. I will particularly concentrate on interesting results obtained from the first wide-band study of PSR J1822-2256 with the uGMRT, which include the detection of a new mode of drifting, existence of disconnected driftbands, bimodality in P3 (i.e., vertical separation between two driftbands), as well as a possible detection of varying spectral index between its different drift modes. I will also report the interaction between observed sub-pulse drifting and nulling properties for PSR J1822-2256. This project, presenting one of the first wide-band studies of single-pulse properties, sheds some light on the frequency dependence of single-pulse characteristics of pulsar emission. Finally, I will discuss the implications of these results for the carousel model of pulsar beam emission.