Constraining the parameters of an isolated neutron star using the lensed HI signal at uGMRT

TL;DR

This paper explores the potential of using gravitational lensing of HI signals by isolated neutron stars at uGMRT to estimate neutron star parameters and enhance detection prospects, contributing to multi-messenger astronomy.

Contribution

It introduces a method to constrain neutron star parameters through HI signal lensing analysis at uGMRT, considering different frequency bands and lensing effects.

Findings

Lensing parameters significantly affect the amplified HI signal observables.

The proposed method can estimate neutron star position and size using signal-to-noise ratios.

The approach is applicable to other radio telescopes with similar specifications.

Abstract

The strength of the HI signal originating from a distant galaxy at a cosmological distance is several orders of magnitude lower than the foreground and background noise and hence it is difficult to observe this signal at a given radio telescope. However, a few recent studies reported the detection of that signal at the radio band suggests the strength of this signal is somehow magnified. In this analysis, we study the prospects of detecting this signal at different frequency bands of the uGMRT where this signal is supposed to be amplified through the strong gravitational lensing by an isolated neutron star located in a cosmological distance. Our study shows the effects of the lensing parameters on the observables of that amplified signal and discusses its variation with the frequency bands considered here. We present a method to estimate the position and size of an isolated neutron star using the signal-to-noise ratio of that signal supposed to be detected at different frequency bands of the uGMRT. We discuss the scope of multi-messenger astronomy in the era of HI observation where the estimated lensing parameters can be cross-validated using the pulsar detection at the X-ray band from the same location in the sky. Our analysis is equally applicable to any radio telescope with given specifications.