Probing Spectral Variability in Binary Millisecond Pulsars: Implications for Propagation Effects and Fast Radio Burst Science

Abstract

Spectral analysis serves as a fundamental diagnostic tool for understanding emission mechanisms, propagation effects, and interactions between pulsar radiation and surrounding material—particularly in binary systems. Fast Radio Bursts (FRBs) often exhibit complex spectral features such as band-limited emission and temporal variability, the origins of which remain poorly understood. Binary millisecond pulsars (MSPs), particularly those showing gigahertz-peaked spectra (GPS) and variable turnover frequencies, offer valuable analogs for probing these effects in a controlled Galactic setting.  Temporal variations in pulsar spectra can provide insights into propagation through the interstellar medium (ISM), and help disentangle intrinsic effects such as GPS, occasionally observed in binary millisecond pulsars. Given the proposed link between compact binaries and fast radio burst (FRB) progenitors, studying spectral evolution in Galactic binary pulsars becomes essential for interpreting FRB phenomenology, including band-limited structures and variability. In this work, we present a case study of PSR J2144–5237, a binary MSP with a 10-day orbital period, and demonstrate a methodology for tracking temporal spectral changes. Our results highlight how binary interactions and variable plasma environments can imprint time-dependent spectral signatures, offering key parallels to FRB behavior. Developing such tools and applying them to Galactic binaries may provide critical insights into the physical conditions driving FRB emission and its variability. The tools developed in our research offer a pathway toward bridging pulsar and FRB studies by applying insights from well-characterized Galactic systems to their extragalactic analogues.