21 cm Power Spectrum Analysis of North Celestial Pole Observations with the Tianlai Dish Pathfinder Array

TL;DR

This paper presents a comprehensive data analysis framework for the Tianlai Dish Pathfinder Array, demonstrating successful power spectrum estimation from 21 cm observations and outlining improvements for future cosmic signal detection.

Contribution

It introduces a validated analysis pipeline for 21 cm intensity mapping with the TDPA, including calibration, foreground removal, and power spectrum estimation, with key improvements for future detection.

Findings

Power spectrum $(k)$ successfully estimated from 107 hours of data.

Pipeline improvements enable future 21 cm signal detection.

Validated analysis framework for 21 cm intensity mapping.

Abstract

The Tianlai Dish Pathfinder Array (TDPA) is a radio interferometer designed to test techniques for 21 cm intensity mapping in the post-reionization universe as a means of measuring large-scale cosmic structure. Using 9 nights of observations targeting the North Celestial Pole (NCP) field, totaling approximately 107 hours of integration time, we analyze data in the frequency range 700-800 MHz (corresponding to redshift $z \sim 0.9$). We do the data format conversion, radio frequency interference (RFI) flagging, calibration, imaging and point source subtraction, and foreground removal via Singular Value Decomposition (SVD). The spherically averaged power spectrum $\Delta^2(k)$ is obtained. This work successfully establishes and validates a comprehensive data analysis framework for the TDPA. We identify key improvements including sky model refinement, increased integration time, and pipeline optimization that will enable future detection of the 21 cm signal through auto-correlation and cross-correlation with optical galaxy surveys.