2023/10/11 by Hale, C. L., Schwarz, D. J., Best, P. N. +17 · 1 citation
#Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2310.07627
Covering ∼5600 deg2 to rms sensitivities of ∼70-100 μJy beam-1, the LOFAR Two-metre Sky Survey Data Release 2 (LoTSS-DR2) provides the largest low-frequency (∼150 MHz) radio catalogue to date, making it an excellent tool for large-area radio cosmology studies. In this work, we use LoTSS-DR2 sources to investigate the angular two-point correlation function of galaxies within the survey. We discuss systematics in the data and an improved methodology for generating random catalogues, compared to that used for LoTSS-DR1, before presenting the angular clustering for ∼900,000 sources ≥1.5 mJy and a peak signal-to-noise ≥7.5 across ∼80% of the observed area. Using the clustering we infer the bias assuming two evolutionary models. When fitting angular scales of 0.5 ≤θ<5 °, using a linear bias model, we find LoTSS-DR2 sources are biased tracers of the underlying matter, with a bias of bC= 2.14+0.22-0.20 (assuming constant bias) and bE(z=0)= 1.79+0.15-0.14 (for an evolving model, inversely proportional to the growth factor), corresponding to bE= 2.81+0.24-0.22 at the median redshift of our sample, assuming the LoTSS Deep Fields redshift distribution is representative of our data. This reduces to bC= 2.02+0.17-0.16 and bE(z=0)= 1.67+0.12-0.12 when allowing preferential redshift distributions from the Deep Fields to model our data. Whilst the clustering amplitude is slightly lower than LoTSS-DR1 (≥2 mJy), our study benefits from larger samples and improved redshift estimates.