The Tianlai-WIYN North Celestial Cap Redshift Survey

TL;DR

This study provides a low redshift galaxy redshift catalog near the North Celestial Pole to aid in 21 cm emission studies, identifying galaxy clusters and analyzing galaxy distribution.

Contribution

It offers a new redshift survey in the NCP region, creating a template for 21 cm intensity mapping and galaxy clustering analysis.

Findings

Number density consistent with other surveys

Identified 11 galaxy cluster candidates

Redshift distribution suitable for 21 cm correlation

Abstract

We present the results of a small, low redshift spectroscopic survey of galaxies within 3 degrees of the North Celestial Pole (NCP) selected using V-band photometry obtained from the North Celestial Cap Survey (NCCS) (Gorbikov & Brosch 2014). The purpose of the current survey is to create a redshift space template for 21 cm emission from neutral hydrogen with which to correlate radio line intensity observations by the Tianlai dish and cylinder interferometers. A total of 898 redshifts were obtained from the 2102 extended objects in the NCCS with m_V < 19 in the survey area. After accounting for extinction, the survey geometry and selection effects, the number density and clustering pattern of galaxies in the redshift catalog are consistent with other low redshift surveys. We were also able to identify 11 galaxy cluster candidates from this redshift catalog.