# The Karl G. Jansky Very Large Array Sky Survey (VLASS). Science case and survey design

## TL;DR

VLASS is a comprehensive, high-resolution radio sky survey covering the entire visible sky, designed to detect variable and transient sources with a focus on multi-wavelength and citizen science engagement.

## Contribution

This paper presents the science case, survey design, and early results of VLASS, a large-scale, high-resolution radio sky survey using the VLA from 2017 to 2024.

## Key findings

- Early survey observations demonstrate the survey's capabilities.
- The survey design effectively balances resolution, sensitivity, and sky coverage.
- Initial data show promising potential for discovering variable radio sources.

## Abstract

The Very Large Array Sky Survey (VLASS) is a synoptic, all-sky radio sky survey with a unique combination of high angular resolution ($\approx$2.5"), sensitivity (a 1$\sigma$ goal of 70 $\mu$Jy/beam in the coadded data), full linear Stokes polarimetry, time domain coverage, and wide bandwidth (2-4 GHz). The first observations began in September 2017, and observing for the survey will finish in 2024. VLASS will use approximately 5500 hours of time on the Karl G. Jansky Very Large Array (VLA) to cover the whole sky visible to the VLA (Declination $>-40^{\circ}$), a total of 33,885 deg$^2$. The data will be taken in three epochs to allow the discovery of variable and transient radio sources. The survey is designed to engage radio astronomy experts, multi-wavelength astronomers, and citizen scientists alike. By utilizing an "on the fly" interferometry mode, the observing overheads are much reduced compared to a conventional pointed survey. In this paper, we present the science case and observational strategy for the survey, and also results from early survey observations.