{
  "bibcode": "2021GCN.30883....1K",
  "body": "D. A. Kann (HETH/IAA-CSIC), A. Rossi (INAF-OAS), A. de Ugarte Postigo \n(HETH/IAA-CSIC, DARK/NBI), C. Thoene, M. Blazek, J. F. Agui Fernandez \n(all HETH/IAA-CSIC), and P. Minguez (CAHA) report:\n\nWe obtained observations of the enhance XRT position (Goad et al., GCN \n30850) of the Swift short GRB 210919A (Tohuvavohu et al., GCN #30846) \nwith CAFOS mounted on the 2.2m telescope at CAHA, Almeria, Spain. We \nobtained 30 x 90 s images in the i' band, starting at 03:38 UT on \nSeptember 19, under good observing conditions.\n\nIn the stacked image, we detect a faint source within the enhanced XRT \nerror circle at:\n\nRA (J2000)   =  05:21:01.098\nDec. (J2000) = +01:18:43.15\n\nwith an error of 0\".5.\n\nCompared to three nearby comparison stars from the PanSTARRS catalog, we \nmeasure:\n\ni' = 24.14 +/- 0.30 mag (AB) @ 0.1525 days after the GRB.\n\nWe suggest this source to be either the afterglow or the host galaxy of \nGRB 210919A.\n\nOther teams have reported upper limits so far:\n\nCR > 18.6 @ 0.007824 d (deepest, Lipunov et al., GCN #30847)\nCR > 17.5 @ 0.002975 d (Hu et al., GCN #30848)\nRc > 20.5, Ic > 18.7 @ 0.05083 - 0.06958 d (Strausbaugh et al., GCN \n#30849)\nRc > 22.1 @ 0.03194 d (Pankov et al., GCN #30851)\nr' > 23.4 @ 0.13125 d, i' > 23.9 @ 0.14458 d (Perley et al., GCN #30852)\nRc > 20.5 @ 0.7208 d (Takamatsu et al., GCN #30855)\nRc > 21.716 @ 0.426 d (AB); r' > 20.16 @ 0.6558 d; i' > 19.107 @ 0.6595 \nd (Kim et al., GCN #30856)\nwhite > 20.8 @ 0.001826 d (Siegel et al., GCN #30857)\nKp > 21.5 @ 0.5542 d (AB) (Zhang et al., GCN #30858)\nr' > 23.6 @ 2.4635 d (Gottlieb et al., GCN #30860)\ni' > 24.1, z' > 23.6 @ 2.343 d (Pierel et al., GCN #30868)\n\nNone of these limits are as deep as our image, with the NOT imaging \n(Perley et al., GCN #30852) slightly earlier and the late DeCam imaging \n(Pierel et al., GCN #30868) coming closest. This leaves it unclear as to \nwhether the source is fading, we can therefore not discern whether it is \nan afterglow candidate or a host-galaxy candidate.\n\nDeeper imaging is needed, if the source is undetected to deeper limits, \nit is very likely the afterglow. If it is the host, it should be \ndetected at higher significance.",
  "circularId": 30883,
  "createdOn": 1632697103000,
  "email": "kann@iaa.es",
  "subject": "GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate",
  "submitter": "Alexander Kann at IAA-CSIC  <kann@iaa.es>",
  "eventId": "GRB 210919A"
}