TITLE: GCN CIRCULAR NUMBER: 33252 SUBJECT: ZTF23aaarlti/AT2023avj: AMI-LA radio detection DATE: 23/02/02 12:50:02 GMT FROM: Lauren Rhodes at Oxford Lauren Rhodes (Oxford), Itai Sfaradi (HUJI), Joe Bright (Oxford), Rob Fender (Oxford), Assaf Horesh (HUJI), David Green (Cambridge), Paul Scott (Cambridge), David Titterington (Cambridge) report: We observed the field of the candidate optical afterglow ZTF23aaarlti (AT2023avj) (Ho et al., GCN 33226) with the Arcminute Microkelvin Imager Large-Array (AMI-LA) at 15.5 GHz beginning at UT 21:46:05.6 on 31-01-2023 for a total of 4 hours. The flux standard 3c286 was used to calibrate the bandpass response and flux scale of the AMI-LA and J0957+5522 was used as an interleaved complex gain calibrator. We detect an unresolved source at a position consistent with the one reported in GCN 33226 with a (preliminary) flux density of 157+/-14uJy/beam (including both a statistical uncertainty and a 5% absolute flux scale uncertainty). Further observations are planned. We thank the staff at the Mullard Radio Astronomy Observatory for carrying out these observations and operating the AMI-LA.