{
  "circularId": 38882,
  "submittedHow": "web",
  "bibcode": "2025GCN.38882....1S",
  "submitter": "Sam Shilling at Lancaster University <shilling.sam@gmail.com>",
  "createdOn": 1736466389079,
  "eventId": "EP250109a",
  "format": "text/plain",
  "subject": "EP250109a: Swift/UVOT non-detection",
  "body": "S. P. R. Shilling (Lancaster U.), S. R. Oates (Lancaster U.), A. A. Breeveld (UCL-MSSL)\nand N. P. M. Kuin (UCL-MSSL) report on behalf of the Swift UVOT team:\n\nSwift/UVOT observed the field of EP250109a (Li et al., GCN 38864) for 938 seconds\nin the U-band starting at 09:22:16 UT, 3 hours after the detection by Einstein Probe WXT.\n\nNo optical afterglow is detected within a 5\" radius of the EP FXT position (Li et al., GCN 38864)\nto a preliminary 3-sigma U-band upper limit of >20.6, calculated using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373).\n\nThe non-detection reported here is consistent with the non-detections reported in other optical\nobservations using the GOTO (Kumar et al., GCN 38868), MASTER (Lipunov et al., GCN 38871), and\nthe SVOM/VT in one of the two filters (Qiu et al., GCN 38872)."
}