{
  "bibcode": "2022GCN.32368....1M",
  "body": "D. B. Malesani (Radboud Univ. and DAWN/NBI), D. Alexander Kann \n(IAA/CSIC), S. D. Vergani (CNRS - Paris Obs./GEPI), L. Izzo (DARK/NBI), \nO. Durfeldt Pedros (NOT and DTU Space), and T. Pursimo (NOT), report on \nbehalf of a larger collaboration:\n\nWe observed the field of GRB 220711B (D'Ai et al., GCN 32366) with the \nNordic Optical Telescope (NOT) equipped with the ALFOSC imager. \nObservations started in twilight in the r band, so that the first images \nare not especially deep. A further set of five 200-s z-band images \nstarted on 2022 Jul 11.90 UT (3.23 hr after the trigger).\n\nClose to the currently available XRT position, we see three sources in \nthe stack of the z-band images (astrometry and photometry are calibrated \nagainst the Gaia and Pan-STARRS catalogs, respectively):\n\n1)\nRA = 17:28:04.49\nDec = +24:40:50.8\nz = 21.78 +- 0.13 AB\n\n2)\nRA = 17:28:04.44\nDec = +24:40:46.7\nz = 22.09 +- 0.15 AB\n\n3)\nRA = 17:28:04.97\nDec = +24:40:44.7\nz = 22.60 +- 0.19 AB\n\nSources 2) and 3) are visible in archival images from the Pan-STARRS \nsurvey, while source 1) is not, which makes it a viable afterglow \ncandidate. However, sources 1), and 2) are slightly outside (5.6\" and \n5.7\" away) the currently available (unenhanced) XRT position (which has \na 3.6\" 90% error radius).\n\nSources 2) and 3) are also detected in our NOT r-band images, while \nsource 1) is not.\n\nThe relation of these sources to GRB 220711B is still under \ninvestigation. Further NOT observations are planned.",
  "circularId": 32368,
  "createdOn": 1657581615000,
  "email": "d.malesani@astro.ru.nl",
  "subject": "GRB 220711B: NOT optical observations",
  "submitter": "Daniele B Malesani at Radboud U  <d.malesani@astro.ru.nl>",
  "eventId": "GRB 220711B"
}