| Name: | Sangita Kumari |
| Affiliation: | National centre for radio astrophysics |
| Conference ID : | ASI2024_941 |
| Title : | First Comprehensive Study on Eclipse Cut-off Frequency Changes in pulsar J1544+4937 and the Reasons Behind Them |
| Authors : | Sangita Kumari
Bhaswati Bhattacharyya
Rahul Sharan
Devojyoti Kansabanik
Benjamin Stappers
Jayanta Roy
|
| Authors Affiliation: | National centre for radio astrophysics, Pune
Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester |
| Mode of Presentation: | Oral |
| Abstract Category : | High Energy Phenomena, Fundamental Physics and Astronomy |
| Abstract : | We report the first systematic study depicting very drastic changes in the eclipse cut-off frequency for the black widow pulsar (BWP) J1544+4937. Majority of such systems often exhibit relatively long duration ~ 15% radio eclipses caused by ablated material from the companion stars (e.g. Polzin et al. 2020). The eclipse observed in such systems are frequency dependent where below a certain frequency (generally denoted as eclipse cut-off frequency) the pulsed signal disappears while the signal is detectable at higher frequencies. PSR J1544+4937 is a Fermi black-widow MSP with spin period 2.16 ms discovered by Giant Metrewave Radio Telescope (GMRT, Bhattacharyya et al. 2013). The previous studies reported an eclipse cut-off frequency of 345 MHz for a few epochs of observations for this system (Kansabanik et al. 2013). We observed a factor of two increase in the cut-off frequency for this system from our observations on 12th February 2022. Later follow-up observations showed that the cut-off frequency is changing with time. In this presentation we will report a systematic study of variation of eclipse cut-off frequency for about a decade, where we observed significant differences in the cut-off frequency values in a few day’s time scale. Such drastic variations in cut-off frequency is not reported for this system or any other spider millisecond pulsar system before. We infer that such changes in the eclipse cut-off frequency depict an eclipse environment for the PSR J1544+4937 system that is dynamically evolving, where, along with the change in electron density, the magnetic field could also be varying. We also report a significant correlation between the eclipse cut-off frequency and the mass loss rate of the companion. This study provides the first direct evidence of mass loss rate affecting the frequency dependent eclipsing in a spider MSP. |
