{
  "submitter": "Sam Shilling at Lancaster University <shilling.sam@gmail.com>",
  "format": "text/plain",
  "submittedHow": "web",
  "createdOn": 1741006685664,
  "bibcode": "2025GCN.39570....1S",
  "subject": "EP250302a: Swift/UVOT detection",
  "body": "S. P. R. Shilling (Lancaster U.) and A. A. Breeveld (UCL-MSSL) reports on behalf of the \nSwift UVOT team:\n \nSwift/UVOT observed the field of EP250302a (Dai et al., GCN 39556) for 1029 seconds\nin the U-band starting at 16:36:56 UT, 1 hour after the detection by Einstein Probe WXT.\n \nA source consistent with the EP-FXT position (Dai et al., GCN 39556) is detected and\nappears to be fading. The preliminary detection magnitudes reported below are calculated\nusing the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373).\nThe magnitude at the start of the observation is 17.64 +/- 0.05 (1 hour post trigger)\nand decays to 18.88 +/- 0.12 (~2 hours post trigger).\n \nWe note that an X-ray source at the EP-FXT position was independently observed by the\nSwift/XRT (Page et al., GCN 39557). We also note that, in addition to the Swift/UVOT,\nvarious other facilities have observed an optical counterpart at this position\n(Zhu et al., GCN 39550; Busmann et al., GCN 39551; Leonini et al., GCN 39553;\nWu et al., GCN 39555; Xin et al., GCN 39558; Lipunov et al., GCN 39559;\nAdami et al., GCN 39560; Becerra et al., GCN 39562; Pankov et al., GCN 39565;\nReguitti et al., GCN 39568; Komesh et al., GCN 39569).",
  "circularId": 39570,
  "eventId": "EP250302a"
}