An analytical method to simulate the HI 21-cm visibility signal for intensity mapping experiments

TL;DR

This paper introduces an analytical approach to efficiently simulate the HI 21-cm visibility signal for intensity mapping, incorporating light-cone effects and telescope response, reducing computational costs for multiple realizations.

Contribution

The paper presents a novel analytical method for simulating HI 21-cm signals that is more efficient than traditional simulation techniques, especially for multiple realizations.

Findings

Validated the method with Ooty Wide Field Array data

Efficiently simulates large numbers of realizations

Incorporates light-cone and chromatic effects

Abstract

Simulations play a vital role in testing and validating HI 21-cm power spectrum estimation techniques. Conventional methods use techniques like N-body simulations to simulate the sky signal which is then passed through a model of the instrument. This makes it necessary to simulate the HI distribution in a large cosmological volume, and incorporate both the light-cone effect and the telescope's chromatic response. The computational requirements may be particularly large if one wishes to simulate many realizations of the signal. In this paper we present an analytical method to simulate the HI visibility signal. This is particularly efficient if one wishes to simulate a large number of realizations of the signal. Our method is based on theoretical predictions of the visibility correlation which incorporate both the light-cone effect and the telescope's chromatic response. We have demonstrated this method by applying it to simulate the HI visibility signal for the upcoming Ooty Wide Field Array Phase I.