{
  "eventId": "EP240506a",
  "bibcode": "2024GCN.36417....1P",
  "createdOn": 1715194101692,
  "submitter": "Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>",
  "subject": "EP240506a: CrAO ZTSH optical upper limit",
  "body": "EP240506a: CrAO ZTSH optical upper limit\n\nN. Pankov (HSE, IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), S. Belkin (IKI) report on behalf of GRB-IKI-FuN collaboration:\n\nWe observed the EP240506a detected by EP-WXT (GCN 36405) with 2.6-meter ZTSh telescope of CrAO, equipped with CCD-photometer and the R-filter. The observations started on 2024-05-07 at 20:43 (UT), i.e. ~1.6 day after EP trigger. The series of 31x120s images were taken.\nWe do not detect any optical object within EP-WXT localization area. The preliminary photometry is following:\n\nDate       UT start  MJD       Exp.    Filter OT    Err.   UL(3sigma)\n                  (mid, days)  (s)\n\n2024-05-07 20:58:29 60437.88266 28x120 R     n/d   n/d     22.5\n\nThe result is in agreement with previous observations (Aryan et al., GCN 36408; Perez-Garcia et al., GCN 36412; Tinyanont et al., GCN 36413).\nWe also do not detect any optical source consistent with the location of WISEA J141556.28-164124.4 reported by Chang et al. (GCN 36414).\nThe variable star SDSS J141557.82-164317.2 mentioned in (Chang et al., GCN 36414) does not show any variability in comparison with USNO-B1.0 (R2=17.02) for which we measure the magnitude of R=16.92 +/- 0.10.\n\nThe magnitudes were calibrated using nearby USNO-B1.0 stars (R2 magnitude). No correction has been made for a Galactic extinction towards the EP240506a.\n\n",
  "circularId": 36417,
  "submittedHow": "email-legacy"
}