VASTER: The ASKAP real-time fast-imaging pipeline – overview and discovery of two long period transients
Abstract Recent developments in widefield radio telescopes have enabled searches of a new region of parameter space in the time domain: timescales of seconds to minutes, that have been overlooked in traditional surveys. These searches have revealed a new population of sources: long period transients, which typically show periodic behaviour of minutes to hours. In addition they have detected phenomena ranging from extreme scintillation to stellar radio bursts. However, almost all searches to date have involved archival data that has been processed in offline, batch mode. In this context, we present VASTER, the first short-timescale imaging and transient detection pipeline running in real time on a widefield radio telescope. VASTER has been running on the Australian SKA Pathfinder (ASKAP) since July 2025, and images most of the ASKAP survey project data on timescales of 15 minutes. In this paper we describe the VASTER system, and present the results from the first two weeks of operation, including the discovery of two long period transients: ASKAP J165130.3–450520 with a period of 6.48 hours and ASKAP J170036.6–445758 with a period of 4.69 hours. The detection of these two sources adds to the small, but growing, population of long period transients, as well as demonstrating the potential of VASTER to explore this region of transient parameter space.
Authors
- Adarsh Bathula (ORCID: https://orcid.org/0000-0001-7947-6703)
- R. M. Shannon (ORCID: https://orcid.org/0000-0002-7285-6348)
- Raghav Girgaonkar (ORCID: https://orcid.org/0000-0002-4678-2939)
- David L. Kaplan (ORCID: https://orcid.org/0000-0001-6295-2881)
- Ashna Gulati (ORCID: https://orcid.org/0000-0001-8802-520X)
- Iris de Ruiter (ORCID: https://orcid.org/0000-0002-4752-5467)
- G. R. Sivakoff (ORCID: https://orcid.org/0000-0001-6682-916X)
- Tara Murphy (ORCID: https://orcid.org/0000-0002-2686-438X)
- Wasim Raja (ORCID: https://orcid.org/0000-0002-6155-9962)
- P. J. Hancock (ORCID: https://orcid.org/0000-0002-4203-2946)
- Dougal Dobie (ORCID: https://orcid.org/0000-0003-0699-7019)
- Shibli Saleheen
- E. Lenc (ORCID: https://orcid.org/0000-0002-9994-1593)
- Jiting Hu
- Yuanming Wang (ORCID: https://orcid.org/0000-0003-0203-1196)
- M Caleb
- Natasha Hurley-Walker
- Alex Massen-Hane
- Yu Wing Joshua Lee
- Joshua Pritchard
- Matthew Whiting
- Raymond Shao
- Lei Zhang
- Owen Cole
- Daniel Mitchell
Institutions
- Commonwealth Scientific and Industrial Research Organisation (AU)
- The University of Sydney (AU)
- University of Alberta (CA)
- Chinese Academy of Sciences (CN)
- Curtin University (AU)
- ARC Centre of Excellence for Gravitational Wave Discovery (AU)
- Astronomy and Space (AU)
- University of Wisconsin–Milwaukee (US)
- Swinburne University of Technology (AU)
Publication Details
- Journal
- Publications of the Astronomical Society of Australia
- Published
- 2026-07-28
- DOI
- https://doi.org/10.1017/pasa.2026.10232
- Primary Topic
- Radio Astronomy Observations and Technology
- Type
- article
- Field-Weighted Citation Impact
- 0.00