First Systematic Study Reporting the Changes in Eclipse Cutoff Frequency for Pulsar J1544+4937

Abstract

We present results from long-term monitoring of frequency-dependent eclipses of the radio emission from PSR J1544+4937, which is a black widow spider millisecond pulsar (MSP) in a compact binary system. The majority of such systems often exhibit relatively long-duration radio eclipses caused by ablated material from their companion stars. With the wide spectral bandwidth of the upgraded Giant Metrewave Radio Telescope, we present the first systematic study of temporal variation of eclipse cutoff frequency. With decade-long monitoring of 39 eclipses for PSR J1544+4937, we notice significant changes in the observed cutoff frequency ranging from 343 ± 7 to ≥740 MHz. We also monitored changes in eclipse cutoff frequency on timescales of tens of days and observed a maximum change of ≥315 MHz between observations that were separated by 22 days. In addition, we observed a change of ∼47 MHz in eclipse cutoff frequency between adjacent orbits, i.e., on timescales of ∼2.9 hr. We infer that such changes in the eclipse cutoff 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 cutoff 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.

Studying the Radio Eclipse of Spider Pulsar J1816+4510 with the FAST

“…However, for a long time, there was a shortage of detailed studies on radio eclipses because of the challenges in observation equipment and the low number of known spider pulsars. The last few years have marked a revival in this field, thanks to the unprecedented development of observation equipment, such as the Low-Frequency Array (LOFAR), Green Bank Telescope, and Five-hundred-meter Aperture Spherical radio Telescope (FAST), etc., and the extensive and novel studies of several eclipsing pulsars, such as PSRs J2215+5135 (Broderick et al 2016), B1957+20 (Fruchter et al 1988(Fruchter et al , 1990Fruchter & Goss 1992;Polzin et al 2020;Bai et al 2022), J1227-4853 (Kudale et al 2020), J1744+4937 (Lyne et al 1990), J2051-0827 (Stappers et al 2001;Polzin et al 2019;Wang et al 2023), J1544+4937 (Bhattacharyya et al 2013;Roy et al 2015), J2055+3829 (Guillemot et al 2019), J1810+1744 (Polzin et al 2018), J1720-0533 (Wang et al 2021), and J1544+4937 (Kumari et al 2023(Kumari et al , 2024, beginning to provide important insights into the nature of eclipsing spider pulsar systems.…”