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GCN Circular 33834

LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
2023-05-20T14:56:35Z (19 days ago)
Dougal Dobie at VAST <>
D. Dobie (Swinburne/OzGrav), A. Gulati (USyd/OzGrav), T. Murphy (USyd/OzGrav) and the JAGWAR collaboration. We have conducted observations of the three candidate optical counterparts to S230518h (GCN 33829) and the X-ray source S230518h_X8 (GCN 33824) with the Australia Telescope Compact Array. Observations were carried out on 2023-05-20 between 02:40 and 13:30 UTC with 2x2048 MHz bands centered on 5.5 and 9 GHz. The array is currently in the compact EW352 configuration and hence we discarded all data from CA06, resulting in a FWHM angular resolution of approximately 30" and 20" at 5.5 GHz and 9 GHz respectively. We detect no radio emission at the location of the optical candidates with the following preliminary 3-sigma upper limits: | Source | 5.5 GHz (uJy) | 9 GHz (uJy) | | SSS23a | <90 | <50 | | SSS23b | <120 | <90 | | SSS23c | <120 | <60 | We detect a radio source consistent with the position of S230518h_X8 with preliminary flux densities of ~350 uJy and ~500 uJy at 5.5 GHz and 9 GHz. This source was also detected by the Rapid ASKAP Continuum Survey in observations on 2019-08-03, suggesting it is unrelated to S230518h. Thank you to CSIRO staff for supporting these observations.
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