The angular two-point correlation of NVSS galaxies revisited

TL;DR

This paper revisits the angular two-point correlation of NVSS radio galaxies, confirming consistency with cosmological models and emphasizing the importance of flux calibration for future surveys.

Contribution

It introduces an improved analysis method using a new mask and accounts for the cosmic radio dipole, enhancing the cosmological interpretation of NVSS data.

Findings

Results are consistent with Planck cosmological model.

A new mask improves the estimation accuracy.

Accounting for the cosmic radio dipole is crucial.

Abstract

We measure the angular two-point correlation and angular power spectrum from the NRAO VLA Sky Survey (NVSS) of radio galaxies. They are found to be consistent with the best-fit cosmological model from the Planck analysis, and with the redshift distribution obtained from the Combined EIS-NVSS Survey Of Radio Sources (CENSORS). Our analysis is based on an optimal estimation of the two-point correlation function and makes use of a new mask, that takes into account direction dependent effects of the observations, sidelobe effects of bright sources and galactic foreground. We also set a flux threshold and take the cosmic radio dipole into account. The latter turns out to be an essential step in the analysis. This improved cosmological analysis of the NVSS emphasizes the importance of a flux calibration that is robust and stable on large angular scales for future radio continuum surveys.