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 (53)

• Astropy: A Community Python Package for Astronomy
• Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
• A New Electron Density Model for Estimation of Pulsar and FRB Distances
• VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
• A periodically active pulsar giving insight into magnetospheric physics
• An Open Catalog for Supernova Data
• unWISE: unblurred coadds of the WISE imaging
• The Fourth Fermi-GBM Gamma-Ray Burst Catalog: A Decade of Data
• The third realization of the International Celestial Reference Frame by very long baseline interferometry
• Spectral properties of 441 radio pulsars
• A powerful bursting radio source towards the Galactic Centre
• The Integral Burst Alert System (IBAS)
• The Caltech-NRAO Stripe 82 Survey (CNSS) Paper I: The Pilot Radio Transient Survey In 50 deg${}^2$
• Duchamp: a 3D source finder for spectral-line data
• A Complete Survey of the Transient Radio Sky and Implications for Gamma-Ray Bursts, Supernovae, and other Relativistic Explosions
• Full-depth Coadds of the WISE and First-year NEOWISE-Reactivation Images
• 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
• A VLA search for 5 GHz radio transients and variables at low Galactic latitudes
• A 22-year Southern Sky Survey for Transient and Variable Radio Sources using the Molonglo Observatory Synthesis Telescope
• Variable and Transient Radio Sources in the FIRST Survey
• The variability timescales and brightness temperatures of radio flares from stars to supermassive black holes
• The Dynamic Radio Sky
• A Systematic Study Of X-Ray Variability In The ROSAT All-Sky Survey
• Caltech-NRAO Stripe 82 Survey (CNSS). III: The First Radio-discovered Tidal Disruption Event, CNSS J0019+00
• New Photometry and Spectra of AB Doradus C: An Accurate Mass Determination of a Young Low-Mass Object with Theoretical Evolutionary Tracks
• Variability of sub-mJy radio sources
• An ASKAP search for a radio counterpart to the first high-significance neutron star-black hole merger LIGO/Virgo S190814bv
• HAZMAT III: The UV Evolution of Mid- to Late-M Stars with GALEX
• A Comprehensive Study of Detectability and Contamination in Deep Rapid Optical Searches for Gravitational Wave Counterparts
• Study of spider pulsar binary eclipses and discovery of an eclipse mechanism transition
• ASKAP Detection of Periodic and Elliptically Polarized Radio Pulses from UV Ceti
• Sensitive Search For Radio Variables And Transients In The Extended Chandra Deep-Field South
• Discovery of the Luminous, Decades-Long, Extragalactic Radio Transient FIRST J141918.9+394036
• GCRT J1742-3001: A New Radio Transient Towards the Galactic Center
• Two years of pulsar observations with the Ultra-Wideband Receiver on the Parkes radio telescope
• A Search for Radio Transients in VLA Archival Images of the 3C 286 Field
• Unsupervised machine learning for transient discovery in Deeper, Wider, Faster light curves
• iPTF Archival Search for Fast Optical Transients
• Diffractive Interstellar Scintillation of the Quasar J1819+3845 at 21cm
• X-ray activity cycle on the active ultra-fast rotator AB Dor A? Implication of correlated coronal and photometric variability
• Flux density variability of 286 radio pulsars from a decade of monitoring
• The GMRT High Resolution Southern Sky Survey for pulsars and transients -II. New discoveries, timing and polarization properties
• A Search for the Near-Infrared Counterpart to GCRT J1745-3009
• Circularly polarized emission from the transient bursting radio source GCRT J1745-3009
• ASKAP observations of multiple rapid scintillators reveal a degrees-long plasma filament
• Radio pulsations from the $\gamma$-ray millisecond pulsar PSR J2039-5617
• 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
• On the optical counterparts of radio transients and variables

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• Constraining the Radio Properties of the $z$=6.44 QSO VIK J2318$-$3113
• Search and identification of transient and variable radio sources using MeerKAT observations: a case study on the MAXI J1820+070 field
• A Flat-Spectrum Radio Transient at 122 Mpc consistent with an Emerging Pulsar Wind Nebula
• Radio Transients and Variables in the Tenth Deeper, Wider, Faster Observing Run
• The Shellless SNR B0532-67.5 in the Large Magellanic Cloud