The Variables and Slow Transients Survey (VAST) on the Australian Square Kilometre Array Pathfinder (ASKAP) is designed to detect highly variable and transient radio sources on timescales from 5 s to ~5 yr. In this paper, we present the survey description, observation strategy and initial results from the VAST Phase I Pilot Survey. This pilot survey consists of ~162 h of observations conducted at a central frequency of 888 MHz between 2019 August and 2020 August, with a typical rms sensitivity of 0.24 mJy beam-1 and angular resolution of 12 -20 arcseconds. There are 113 fields, each of which was observed for 12 min integration time, with between 5 and 13 repeats, with cadences between 1 day and 8 months. The total area of the pilot survey footprint is 5 131 square degrees, covering six distinct regions of the sky. An initial search of two of these regions, totalling 1 646 square degrees, revealed 28 highly variable and/or transient sources. Seven of these are known pulsars, including the millisecond pulsar J2039-5617. Another seven are stars, four of which have no previously reported radio detection (SCR J0533-4257, LEHPM 2-783, UCAC3 89-412162 and 2MASS J22414436-6119311). Of the remaining 14 sources, two are active galactic nuclei, six are associated with galaxies and the other six have nomulti-wavelength counterparts and are yet to be identified.
|Journal||Publications of the Astronomical Society of Australia|
|Publication status||Published - 12 Oct 2021|