Cosmology from LOFAR Two-metre Sky Survey Data Release 2: Angular Clustering of Radio Sources

arXiv (Cornell University)

Abstract

Covering $\sim$5600 deg$^2$ to rms sensitivities of $\sim$70$-$100 $μ$Jy beam$^{-1}$, the LOFAR Two-metre Sky Survey Data Release 2 (LoTSS-DR2) provides the largest low-frequency ($\sim$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 $\sim$900,000 sources $\geq$$1.5$ mJy and a peak signal-to-noise $\geq$$7.5$ across $\sim$$80\%$ of the observed area. Using the clustering we infer the bias assuming two evolutionary models. When fitting {angular scales of $0.5 \leqθ<5\,°$, using a linear bias model, we find LoTSS-DR2 sources are biased tracers of the underlying matter, with a bias of $b_{C}= 2.14^{+0.22}_{-0.20}$ (assuming constant bias) and $b_{E}(z=0)= 1.79^{+0.15}_{-0.14}$ (for an evolving model, inversely proportional to the growth factor), corresponding to $b_E= 2.81^{+0.24}_{-0.22}$ at the median redshift of our sample, assuming the LoTSS Deep Fields redshift distribution is representative of our data. This reduces to $b_{C}= 2.02^{+0.17}_{-0.16}$ and $b_{E}(z=0)= 1.67^{+0.12}_{-0.12}$ when allowing preferential redshift distributions from the Deep Fields to model our data. Whilst the clustering amplitude is slightly lower than LoTSS-DR1 ($\geq$2 mJy), our study benefits from larger samples and improved redshift estimates.

Authors 17

1. Catherine Laura Hale

   Royal Observatory · UK Astronomy Technology Centre

   Affiliation as printed

   Institute for Astronomy , School of Physics and Astronomy , University of Edinburgh , Royal Observatory Edinburgh , Blackford Hill , Edinburgh , EH9 3HJ , UK

2. Dominik J. Schwarz
3. P. N. Best

   Royal Observatory · UK Astronomy Technology Centre

   Affiliation as printed

   Institute for Astronomy , School of Physics and Astronomy , University of Edinburgh , Royal Observatory Edinburgh , Blackford Hill , Edinburgh , EH9 3HJ , UK

4. Szymon J. Nakoneczny

   California Institute of Technology

   Affiliation as printed

   Department of Astrophysics , National Centre for Nuclear Research , Pasteura 7 , 02-093 Warsaw , Poland

   Division of Physics, Mathematics, and Astronomy , California Institute of Technology , 1200 E California Blvd , Pasadena , CA , 91125 , USA

5. D. Alonso

   University of Oxford

   Affiliation as printed

   Department of Physics , University of Oxford , Denys Wilkinson Building , Keble Road , Oxford OX1 3RH , UK

6. David Bacon

   University of Portsmouth

   Affiliation as printed

   Institute of Cosmology and Gravitation , University of Portsmouth , Dennis Sciama Building , Burnaby Road , Portsmouth PO1 3FX , United Kingdom

7. Maciej Bilicki

   Center for Theoretical Physics · Polish Academy of Sciences

   Affiliation as printed

   Center for Theoretical Physics , Polish Academy of Sciences , al. Lotników 32/46 , 02-668 Warsaw , Poland

8. S. Camera
9. Caroline S. Heneka

   Heidelberg University

   Affiliation as printed

   Institut für Theoretische Physik , Fakultät für Physik und Astronomie , Universität Heidelberg , Philosophenweg 16 , 69120 Heidelberg , Germany

10. Morteza Pashapour-Ahmadabadi

    Bielefeld University

    Affiliation as printed

    Fakultät für Physik , Universität Bielefeld , Postfach 100131 , 33501 Bielefeld , Germany

11. Prabhakar Tiwari

    Chinese Academy of Sciences · National Astronomical Observatories

    Affiliation as printed

    National Astronomical Observatories , Chinese Academy of Science , Beijing , 100101 , P.R.China

12. K. J. Duncan

    Royal Observatory · UK Astronomy Technology Centre

    Affiliation as printed

    Institute for Astronomy , School of Physics and Astronomy , University of Edinburgh , Royal Observatory Edinburgh , Blackford Hill , Edinburgh , EH9 3HJ , UK

13. M. J. Jarvis

    California Institute of Technology · University of the Western Cape

    Affiliation as printed

    Department of Physics & Astronomy , University of the Western Cape , Cape Town 7535 , South Africa

    Division of Physics, Mathematics, and Astronomy , California Institute of Technology , 1200 E California Blvd , Pasadena , CA , 91125 , USA

14. R. Kondapally

    Royal Observatory · UK Astronomy Technology Centre

    Affiliation as printed

    Institute for Astronomy , School of Physics and Astronomy , University of Edinburgh , Royal Observatory Edinburgh , Blackford Hill , Edinburgh , EH9 3HJ , UK

15. M. Magliocchetti

    National Institute for Astrophysics

    Affiliation as printed

    INAF-IAPS , via Fosso del Cavaliere 100 , 00133 , Rome , Italy

16. Huub J. A. Röttgering Aachen Leiden Observatory

    Leiden University · Leiden Observatory

    Affiliation as printed

    Leiden Observatory , Leiden University , PO Box 9513 , NL-2300 RA Leiden , The Netherlands

17. T. W. Shimwell Aachen Leiden Observatory

    Leiden University · Leiden Observatory · Netherlands Institute for Radio Astronomy

    Affiliation as printed

    ASTRON , Netherlands Institute for Radio Astronomy , Oude Hoogeveensedijk 4 , 7991 PD , Dwingeloo , The Netherlands

    Leiden Observatory , Leiden University , PO Box 9513 , NL-2300 RA Leiden , The Netherlands