| Name: Amar Chandra |
| Affiliation: Aryabhatta Research Institute of Observational Sciences |
| Conference ID: ASI2026_679 |
| Title: Cyclic changes in pulse shape and single pulse properties of PSR J0742-2822 |
| Abstract Type: Poster |
| Abstract Category: High Energy Phenomena, Fundamental Physics and Astronomy |
| Author(s) and Co-Author(s) with Affiliation: Amar Deo Chandra(Aryabhatta Research Institute of Observational Sciences, Nainital-263001, India), Yashwant Gupta(National Centre for Radio Astrophysics, Pune-411007, India), Andrew G. Lyne(University of Manchester, Manchester-M13 9PL, UK) |
| Abstract: Though the majority of pulsars have very stable pulse profiles, there are a few that show changes with time, and these can be very important tools for understanding the pulsar emission mechanism. Here, we report on very interesting and rather unique changes in pulse shape and single pulse behaviour of PSR J0742-2822, using simultaneous dual-band observations with the GMRT at 325 MHz and 610 MHz, along with L-band data from the Jodrell Bank Observatory. We find clear evidence of cyclic changes on time scales of about 200 days, in the pulse width and shape in the data at all three frequencies, which can be separated into two distinct profile modes having distinctly different pulse shapes and single pulse properties, as shown by their fluctuation spectra. Decomposing the profile into core and conal emission components, we show varying retardation-aberration effects for the conal components in the two modes. Using this, along with the available knowledge of the rotation geometry of this pulsar, we can make estimates for emission heights of the core and conal components as well as the footpoints of the field lines, in the two modes of emission. We present a detailed characterisation of the possible rearrangements of the emission regions in the magnetosphere, as the pulsar switches between the two states. This makes it one of the few unique pulsars showing profile shape variations, where such a study has been done. |
