COSMOS VLA 3GHz Catalog Definitions

Overview

The catalog contains sources selected down to a 5 sigma (sigma~2.3 uJy/beam) threshold. This catalog can be used for statistical analyses, accompanied with the corrections given in the data & catalog release paper (Smolcic et al. 2016). All completeness & bias corrections and source counts presented in Smolcic et al. (2016) were calculated using this sample. The total fraction of spurious sources in the COSMOS 2 sq.deg. is below 2.7% within this catalog. However, an increase of spurious sources (up to 24% at 5.0<S/N<5.5) is present (for details see Sec. 5.2., Fig. 16 and Tab 3 in the data & catalog release paper). A subsample with a minimal spurious source fraction can be selected by requiring a signal-to-noise ratio SNR ≥ 5.5 (see Sec. 5.2., Fig. 16 and Tab 3 in the data & catalog release paper). The total fraction of spurious sources in the COSMOS 2 sq.deg. within such a selected sample is below 0.4%, and the fraction of spurious sources is below 3% even at the lowest SNR (=5.5).

Name	Intype	Units	Description
id	int		Source ID
name	char		IAU standard name
ra	double	deg	Right Ascension (J2000)
ra_err	float	arcsec	Positional error in RA
dec	double	deg	Declination (J2000)
dec_err	float	arcsec	Positional error in Dec
flux	float	uJy	Total integrated flux density at 3 GHz
flux_err	float	uJy	Error on the total integrated flux density
rms	float	uJy/beam	Local rms noise at the source position
snr	float		Signal-to-noise ratio
npix	int		Number of pixels used for flux density integration
res	int		Resolved flag
multi	int		Multi-component flag