The ASKAP Variables and Slow Transients (VAST) Pilot Survey

Abstract

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 seconds to $\sim 5$ years. 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 $\sim 162$ hours 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, \red{each of which was observed for 12 minutes 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 no multiwavelength counterparts and are yet to be identified.

References in corpus (19)

• A New Electron Density Model for Estimation of Pulsar and FRB Distances
• A periodically active pulsar giving insight into magnetospheric physics
• unWISE: unblurred coadds of the WISE imaging
• The third realization of the International Celestial Reference Frame by very long baseline interferometry
• SubmilliJansky Transients in Archival Radio Observations
• Deep Full-sky Coadds from Three Years of WISE and NEOWISE Observations
• A Flare-Type IV Burst Event from Proxima Centauri and Implications for Space Weather
• The variability timescales and brightness temperatures of radio flares from stars to supermassive black holes
• An ASKAP search for a radio counterpart to the first high-significance neutron star-black hole merger LIGO/Virgo S190814bv
• ASKAP Detection of Periodic and Elliptically Polarized Radio Pulses from UV Ceti
• Two years of pulsar observations with the Ultra-Wideband Receiver on the Parkes radio telescope
• Unsupervised machine learning for transient discovery in Deeper, Wider, Faster light curves
• Flux density variability of 286 radio pulsars from a decade of monitoring
• A Search for the Near-Infrared Counterpart to GCRT J1745-3009
• ASKAP observations of multiple rapid scintillators reveal a degrees-long plasma filament
• Prospects for Discovering Pulsars in Future Continuum Surveys Using Variance Imaging
• Keeping up with the cool stars: One TESS year in the life of AB Doradus
• Calculating transient rates from surveys
• The milliarcsecond-scale radio structure of AB Dor A

Cited by in corpus (1)

• A Case for a Binary Black Hole System Revealed via Quasi-Periodic Outflows