Enhancing Neutral Hydrogen (HI) Detection in Galaxies through Optimized Matched Filter Analysis

Abstract

Neutral Hydrogen (HI) is a fundamental component in the composition of galaxies, providing crucial insights into their structure and dynamics. In this research, we propose a novel approach to improve the detection of H1 spectral lines in radio telescope data by employing a matched filter algorithm. The algorithm capitalizes on the convolution of a template function, optimized using the "Busy" function that defines the line profile properties, with a randomly generated H1 peak. This H1 peak is subsequently embedded within noisy data, accounting for the effects of telescope measurements, such as thermal broadening and radio-frequency interference. The incorporation of the Voigt profile in the noise generation ensures a realistic representation of these effects. Through comprehensive analysis, we demonstrate that a matched filter with a multi-layered convolution scheme yields the highest efficiency in recovering H1 peaks. The effectiveness of peak recovery is shown to be influenced by the injected noise profiles, allowing for a direct comparison of the matched filter’s performance concerning the Integrated and Peak Signal to Noise ratios. This research contributes to the advancement of observational techniques in astrophysics and deepens our understanding of the distribution and properties of Neutral Hydrogen in galaxies. It represents the first such exploration of this technique in the context of the Canadian Hydrogen Observatory and Radio Transient Detector (CHORD), which is under construction at the Dominion Radio Astronomy Observatory in Penticton, BC and which will survey the HI sky more broadly and deeply than has been previously possible.