{
  "bibcode": "2021GCN.30551....1K",
  "body": "D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, \nDARK/NBI), C. Thoene, M. Blazek, J. F. Agui Fernandez (all \nHETH/IAA-CSIC), A. Gardini, and I. Hermelo (both CAHA) report:\n\nWe observed the in-flight XRT afterglow position (revised in Evans et \nal., GCN #30547) of GRB 210724A (D'Avanzo et al., GCN #30497) with CAFOS \nmounted at the 2.2m Calar Alto telescope (Almeria, Spain), under very \nadverse conditions (high airmass, strong Calima, clouds, bad seeing, \nstrong moonlight - the works). We obtained 10 x 180 s images in r', \nstarting on July 24, 21:07:08 UT (0.8831 h after the burst).\n\nAt the position of the GTC afterglow candidate (de Ugarte Postigo et \nal., GCN #30511), we detect no source down to r' > 22.0 mag (AB \nmagnitude) against PanSTARRS comparison stars, at midtime 0.0482 d \n(1.1569 h) after the burst. This is of similar depth as the detection by \nde Ugarte Postigo et al., GCN #30511, perhaps indicating a slowly rising \nafterglow, or at least one that is not steeply decaying.",
  "circularId": 30551,
  "createdOn": 1627648630000,
  "email": "kann@iaa.es",
  "subject": "GRB 210724A: Early CAHA 2.2m limit",
  "submitter": "Alexander Kann at IAA-CSIC  <kann@iaa.es>",
  "eventId": "GRB 210724A"
}