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GCN Circular 33253

ZTF23aabmzlp/AT2023azs: VLA radio detection
2023-02-02T16:00:45Z (a year ago)
Daniel Perley at Liverpool JMU <>
D. A. Perley (LJMU) reports on behalf of a larger collaboration:

We observed the location of the fast optical transient ZTF23aabmzlp/AT2023azs (Andreoni et al., GCN 33229) using the Karl G. Jansky Very Large Array (VLA) on 2023 January 31 between 04:49 and 05:23 (UT).  Observations were carried out using the X-band receivers at a mean frequency of 10 GHz.

We detect a source at a location of RA = 11:30:16.468, Dec=+65:51:10.007 (J2000; RMS statistical accuracy +/- 0.02"), consistent with the optical position.  The flux density is 136 (+/- 6) microJy at 9 GHz and 76 (+/- 7) microJy at 11 GHz.  The mean observation time is approximately 59975.22, 2.96 days after the first reported optical detection.

The detection of radio emission supports the conclusion that the source is the afterglow of a relativistic explosion at cosmological distance.  The unusual spectral index is likely due to interstellar scintillation.

We thank the VLA staff for rapidly scheduling and executing these observations.

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