An Ultra-deep Multi-band VLA Survey of the Faint Radio Sky (COSMOS-XS): Source Catalog and Number Counts

Abstract

We present ultra-deep, matched-resolution Karl G. Jansky Very Large Array (VLA) observations at 10 and $3$ GHz in the COSMOS field: the COSMOS-XS survey. The final 10 and $3$ GHz images cover $\sim 16{\mathrm{arcmin}}^2$ and $\sim 180{\mathrm{arcmin}}^2$ and reach median rms values of $0.41\mu {\mathrm{Jy}\mathrm{beam}}^{-1}$ and $0.53\mu {\mathrm{Jy}\mathrm{beam}}^{-1}$, respectively. Both images have an angular resolution of $\sim 2.0^{\prime \prime }$. To fully account for the spectral shape and resolution variations across the broad bands, we image all data with a multi-scale, multi-frequency synthesis algorithm. We present source catalogs for the 10 and $3$ GHz image with 91 and 1498 sources, respectively, above a peak brightness threshold of $5\sigma$. We present source counts with completeness corrections included that are computed via Monte Carlo simulations. Our corrected radio counts at $3$ GHz with direct detections down to $\sim 2.8\mu$Jy are consistent within the uncertainties with other results at 3 and 1.4 GHz, but extend to fainter flux densities than previous direct detections. The ultra-faint $3$ GHz number counts are found to exceed the counts predicted by the semi-empirical radio sky simulations developed in the framework of the SKA Simulated Skies project, consistent with previous P(D) analyses. Our measured source counts suggest a steeper luminosity function evolution for these faint star-forming sources. The semi-empirical Tiered Radio Extragalactic Continuum Simulation (T-RECS) predicts this steeper evolution and is in better agreement with our results. The $10$ GHz radio number counts also agree with the counts predicted by the T-RECS simulation within the expected variations from cosmic variance. In summary, the multi-band, matched-resolution COSMOS-XS survey in the well-studied COSMOS field provides a high-resolution view of the ultra-faint radio sky that can help guide next generation radio facilities.

Resubmitted to ApJ after incorporating suggestions from the referee; 20 pages, 17 figures. This is a companion paper to Algera et al., on arXiv today

References in corpus (29)

• The NumPy array: a structure for efficient numerical computation
• Cosmic Star Formation History
• Star Formation in AEGIS Field Galaxies since z=1.1 : The Dominance of Gradually Declining Star Formation, and the Main Sequence of Star-Forming Galaxies
• UV Star Formation Rates in the Local Universe
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• The Herschel view of the dominant mode of galaxy growth from z=4 to the present day
• The Relation Between SFR and Stellar Mass for Galaxies at 3.5 $\le z\le$ 6.5 in CANDELS
• An optimized algorithm for multi-scale wideband deconvolution of radio astronomical images
• The VLA-COSMOS Survey: II. Source Catalog of the Large Project
• GOODS-HERSCHEL: star formation, dust attenuation and the FIR-radio correlation on the Main Sequence of star-forming galaxies up to z~4
• The Star Formation History of the Universe as Revealed by Deep Radio Observations
• The far-infrared/radio correlation and radio spectral index of galaxies in the SFR-M* plane up to z 2
• The Radio Spectral Energy Distribution and Star Formation Rate Calibration in Galaxies
• CANDELS Multiwavelength Catalogs: Source Identification and Photometry in the CANDELS COSMOS Survey Field
• The Deep SWIRE Field I. 20cm Continuum Radio Observations: A Crowded Sky
• VLA and ALMA Imaging of Intense, Galaxy-Wide Star Formation in z ~ 2 Galaxies
• The VLA-COSMOS Survey: III. Further Catalog Analysis and the Radio Source Counts
• The 1.28 GHz MeerKAT DEEP2 Image
• The cosmic evolution of radio-AGN feedback to z=1
• A catalogue of micro-Jy radio sources in northern legacy fields
• Galaxy Evolution in the Radio Band: The Role of Starforming Galaxies and Active Galactic Nuclei
• The dust un-biased cosmic star formation history from the 20 cm VLA-COSMOS survey
• Spitzer Observations of the z=2.73 Lensed Lyman Break Galaxy, MS1512-cB58
• Modeling the spectral energy distribution of ULIRGs I: the radio spectra
• Star formation rates in Lyman break galaxies: radio stacking of LBGs in the COSMOS field and the sub-$\mu$Jy radio source population
• A physical model for the evolving UV luminosity function of high redshift galaxies and their contribution to the cosmic reionization
• The faint radio sky: VLBA observations of the COSMOS field
• A Multi-wavelength Analysis of the Faint Radio Sky (COSMOS-XS): the Nature of the Ultra-faint Radio Population

Cited by in corpus (23)

• The infrared-radio correlation of star-forming galaxies is strongly M${}_{\star }$-dependent but nearly redshift-invariant since z$\sim$4
• AGN Selection and Demographics in GOODS-S/HUDF from X-ray to Radio
• Mapping Obscuration to Reionization with ALMA (MORA): 2mm Efficiently Selects the Highest-Redshift Obscured Galaxies
• Source Counts Spanning Eight Decades of Flux Density at 1.4 GHz
• The LOFAR Two-metre Sky Survey: the radio view of the cosmic star formation history
• MIGHTEE: Deep 1.4 GHz Source Counts and the Sky Temperature Contribution of Star Forming Galaxies and Active Galactic Nuclei
• Predicting sub-millimeter flux densities from global galaxy properties
• The LOFAR Two-metre Sky Survey Deep fields: A new analysis of low-frequency radio luminosity as a star-formation tracer in the Lockman Hole region
• An ultra-deep multi-band VLA survey of the faint radio sky (COSMOS-XS): New constraints on the cosmic star formation history
• The cosmic radio background from 150 MHz--8.4 GHz, and its division into AGN and star-forming galaxy flux
• Heavily Obscured AGN detection: a Radio vs X-ray challenge
• A deep 1.4 GHz survey of the J1030 equatorial field: a new window on radio source populations across cosmic time
• COLDz: Deep 34 GHz Continuum Observations and Free-free Emission in High-redshift Star-forming Galaxies
• COLDz: Probing Cosmic Star Formation With Radio Free-free Emission
• The LOFAR Two-metre Sky Survey: Deep Fields Data Release 2. I. The ELAIS-N1 field
• The Long and the Short of It: The Benefits and Leverage of Ultraviolet-Radio Galaxy Fitting
• SPARCS-North Wide-field VLBI Survey: Exploring the resolved MicroJy extra-galactic radio source population with EVN+e-MERLIN
• Tomography of the environment of the COSMOS/AzTEC-3 submillimeter galaxy at z=5.3 revealed by Lyalpha and MUSE observations
• Behind the dust veil: A panchromatic view of an optically dark galaxy at z=4.82
• Pulsar B1237+25 Aberration/Retardation Analysis from Decimeter to Decameter Wavelength: Challenge to "Radius-to-Frequency Mapping"
• SEMPER I. Radio Predictions for Star-Forming Galaxies at $0<z<5$
• An empirical model of the extragalactic radio background
• MIGHTEE: total intensity radio continuum imaging and the COSMOS / XMM-LSS Early Science fields