The VLA‐COSMOS 3 GHz Large Project: Continuum data and source catalog release
Résumé
We present the VLA‐COSMOS 3 GHz Large Project based on 384 h of observations with the Karl G. Jansky Very Large Array (VLA) at 3 GHz (10 cm) toward the two square degree Cosmic Evolution Survey (COSMOS) field. The final mosaic reaches a median rms of 2.3 degrees Jy beam 1 over the two square degrees at an angular resolution of 0.75 `'. To fully account for the spectral shape and resolution variations across the broad (2 GHz) band, we image all data with a multiscale, multifrequency synthesis algorithm. We present a catalog of 10 830 radio sources down to 5 degrees, out of which 67 are combined from multiple components. Comparing the positions of our 3 GHz sources with those from the Very Long Baseline Array (VLBA)‐COSMOS survey, we estimate that the astrometry is accurate to 0 : 01 0 0 at the bright end (signal‐to‐noise ratio, S = N3 GHz > 20). Survival analysis on our data combined with the VLA‐COSMOS 1.4 GHz Joint Project catalog yields an expected median radio spectral index of alpha = 0 : 7. We compute completeness corrections via Monte Carlo simulations to derive the corrected 3 GHz source counts. Our counts are in agreement with previously derived 3 GHz counts based on single‐pointing (0 : 087 square degrees) VLA data. In summary, the VLA‐COSMOS 3 GHz Large Project simultaneously provides the largest and deepest radio continuum survey at high (0.75 `') angular resolution to date, bridging the gap between last‐generation and next‐generation surveys.
Domaines
Astrophysique [astro-ph]| Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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