{
  "createdOn": 1777546221209,
  "bibcode": "2026GCN.44432....1C",
  "eventId": "EP260430a",
  "circularId": 44432,
  "submittedHow": "web",
  "format": "text/plain",
  "submitter": "Jonathan Quirola at Radboud University <jaquirola1990@gmail.com>",
  "body": "J. A. Chácon (PUC), F. E. Bauer (SSI and UTA), D. B. Malesani (DAWN/NBI and Radboud), J. Quirola-Vasquez (Radboud), A. J. Levan (Radboud & Warwick), P. G. Jonker (Radboud), R. A. J. Eyles-Ferris (Leicester), report on behalf of a larger collaboration:\n\nWe observed the field of the fast X-ray transient EP260430a (Wang et al., GCN 44427) using LCO 1m telescopes located at the Cerro Tololo Inter-American Observatory (Chile) equipped with the SINISTRO instrument. A series of 6x300 s exposures was taken using the SDSS-r filter, starting at 2026-04-30 03:32:35 UT (~1 hr after the trigger).\n\nNo new source is detected within or at the border of the EP/FXT uncertainty region (Wang et al., GCN 44427). From the stacked images, we obtain the following 3-sigma upper limit:
\n\nr > 22.1\n\nThis upper limit is in AB magnitudes, calibrated using nearby stars from the Pan-STARRS catalog, and is not corrected for Galactic extinction.\n",
  "subject": "EP260430a: LCO optical upper limits"
}