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A search for radio afterglows from gamma-ray bursts with the Australian Square Kilometre Array Pathfinder.
- Source :
-
Monthly Notices of the Royal Astronomical Society . May2021, Vol. 503 Issue 2, p1847-1863. 17p. - Publication Year :
- 2021
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Abstract
- We present a search for radio afterglows from long gamma-ray bursts using the Australian Square Kilometre Array Pathfinder (ASKAP). Our search used the Rapid ASKAP Continuum Survey, covering the entire celestial sphere south of declination +41○, and three epochs of the Variables and Slow Transients Pilot Survey (Phase 1), covering ∼5000 square degrees per epoch. The observations we used from these surveys spanned a nine-month period from 2019 April 21 to 2020 January 11. We cross-matched radio sources found in these surveys with 779 well-localized (to ≤15 arcsec) long gamma-ray bursts occurring after 2004 and determined whether the associations were more likely afterglow- or host-related through the analysis of optical images. In our search, we detected one radio afterglow candidate associated with GRB 171205A, a local low-luminosity gamma-ray burst with a supernova counterpart SN 2017iuk, in an ASKAP observation 511 d post-burst. We confirmed this detection with further observations of the radio afterglow using the Australia Telescope Compact Array at 859 and 884 d post-burst. Combining this data with archival data from early-time radio observations, we showed the evolution of the radio spectral energy distribution alone could reveal clear signatures of a wind-like circumburst medium for the burst. Finally, we derived semi-analytical estimates for the microphysical shock parameters of the burst: electron power-law index p = 2.84, normalized wind-density parameter A * = 3, fractional energy in electrons ϵe = 0.3, and fractional energy in magnetic fields ϵ B = 0.0002. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 503
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 149653185
- Full Text :
- https://doi.org/10.1093/mnras/stab326