Galaxy power spectrum and biasing results from the LOFAR Two-metre Sky Survey (first data release)

TL;DR

This paper analyzes the first data release of the LOFAR Two-metre Sky Survey to assess its data quality, understand systematics, and measure galaxy clustering, demonstrating its potential for large-scale cosmological studies.

Contribution

It evaluates survey systematics, measures galaxy clustering, and employs Bayesian analysis to determine galaxy biasing, establishing LOFAR DR1's suitability for cosmological research.

Findings

Galaxy clustering fits $\\Lambda$CDM model reasonably well.

Survey systematics and flux calibration fluctuations identified.

LOFAR DR1 is suitable for large-scale cosmological studies after masking noisy regions.

Abstract

The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing survey aiming to observe the entire Northern sky, providing an excellent opportunity to study the distribution and evolution of the large-scale structure of the Universe. The source catalogue from the public LoTSS first data release (DR1) covers 1% of the sky, and shows correlated noise or fluctuations of the flux density calibration on few degree scales. We explore the LoTSS DR1 to understand the survey systematics and data quality of this first data release. We produce catalog mocks to estimate uncertainties, and measure the angular clustering statistics of LoTSS galaxies, which fit the $\Lambda$CDM cosmology reasonably well. We employ a Markov chain Monte Carlo (MCMC) based Bayesian analysis to recover the best galaxy biasing scheme and multi-component source fraction for LoTSS DR1 above $1$ mJy assuming different possible redshift templates. After masking some noisy and uneven patches and with suitable flux density cuts, the LOFAR survey appears qualified for large-scale cosmological studies. The upcoming data releases from LOFAR are expected to be deeper and wider, and will therefore provide improved cosmological measurements.