The CHILES Continuum & Polarization Survey-II: Radio Continuum Source Catalog and Radio Properties

Abstract

The COSMOS HI Large Extragalactic Survey (CHILES) Continuum & Polarization (CHILES Con Pol) survey is an ultra-deep continuum imaging study of the COSMOS field conducted using the Karl G. Jansky Very Large Array. We obtained 1000 hours of L-band ($\lambda = 20$ cm) observations across four spectral windows (1.063-1.831 GHz) on a single pointing and produced a confusion limited image with an apparent RMS noise of 1.67 $\mu$Jy beam$^{-1}$ with a synthesized beam of 5$.\!\!^{\prime\prime}$5$\times$5$.\!\!^{\prime\prime}$0. This paper reports a 1.4 GHz radio continuum source catalog containing 1678 sources detected above 7$\sigma$ (flux densities greater than 11.7 $\mu$Jy), identified using two independent source extraction programs applied to the Stokes $I$ image. Resolved sources dominate at flux density S$_{1.4GHz} \ge 42 $\mu$Jy. Radio spectral index for each source was derived using a power-law fit across the four spectral windows, and we found that a robust spectral index measurement requires a total signal-to-noise ratio of at least 20. Comparisons with previous 1.4 GHz radio continuum surveys show good overall consistency, but evidence for a high degree of catalog incompleteness and the effects of source confusion are evident for some of the earlier studies.