The VLA Sky Survey (VLASS): Technical Implementation and Pilot Survey Results

The VLA Sky Survey (VLASS) is a 5520 hour project to survey the 33885 square degrees of the sky above Declination -40 degrees from 2-4 GHz at 2.5" angular resolution using the upgraded Karl G. Jansky Very Large Array (VLA). Over the survey duration of 7 years, each area of the sky will be covered in 3 epochs spaced 32 months apart, to a depth of 0.12mJy/beam rms noise per epoch and 0.07mJy/beam for 3 epochs combined. Pilot observations were taken in mid-2016, with the full survey to start in September 2017. The raw data will be available in the NRAO archive immediately with no proprietary period and science data products will be provided to the community in a timely manner. Basic Data Products (BDP) that will be produced by the survey team include: raw and calibrated visibility data, quick-look continuum images, single-epoch images and spectral image cubes, single-epoch basic object catalogs, and cumulative "static sky" images and image cubes and basic object catalogs to the full survey depth. Single-epoch and cumulative images are in intensity and linear polarization (Stokes IQU). In addition to the BDP provided by NRAO and served through the NRAO archive, there are opportunities for Enhanced Data Products and Services that are provided by the community in partnership with the VLASS team.In this presentation we describe the survey design and the Technical Implementation Plan (TIP) for the VLASS, and report on results from the VLASS Pilot observations. The pilot survey covered 2480 unique square degrees, with 2160 square degrees within the SDSS/FIRST footprint. The pilot also covered key deep fields including COSMOS, GOODS-N, CDFS, Elais-N1, and the SDSS Stripe-82. Preliminary imaging and comparisons have been carried out for selected pilot fields as part of early science verification. We also discuss the technical issues and challenges remaining to be addressed before commencing the survey and our plans moving forward. There are also opportunities for community involvement in VLASS technical areas, including the involvement of undergraduate and graduate students in science verification and commissioning activities.