VLA Sky Survey

by Davis Murphy last modified Mar 16, 2020 by Mark Lacy

The Very Large Array Sky Survey (VLASS) is a community-driven initiative to carry out a synoptic radio sky survey using the Karl G. Jansky Very Large Array (VLA). VLASS will eventually use ~ 5500 hours to cover the whole sky visible at the VLA (δ > -40 deg), a total of 33,885 deg². The survey is designed to engage radio astronomy experts, multi-wavelength astronomers, and citizen scientists alike. The data will be acquired in three epochs to allow the discovery of transient radio sources; is calibrated in Stokes I, Q and U; and will cover the frequency range 2–4 GHz with an angular resolution of ~ 2.5 arcsec. The 1σ  sensitivity goal for a single pass is 120 μJy, or 69 μJy when all three passes are combined. Observing began in September 2017 and the survey will finish observing in 2024. By utilizing an “on the fly” interferometry mode, the observing overheads are much reduced compared to a conventional pointed survey.

Motivation: In the 20 years since the initial observations were made for the NRAO VLA Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST), these pioneering programs have defined the state-of-the-art in centimeter radio sky surveys and produced a steady stream of excellent science. The astronomy community recognized that several of the high priority science goals of the 2010 decadal survey New Worlds, New Horizons in Astronomy and Astrophysics could be addressed by a new VLA sky survey. Many scientists expressed keen interest in a new, wide-area centimeter wavelength sky surveys in support of multi-wavelength synoptic surveys using existing and future facilities, such as the Large Synoptic Survey Telescope.