{
  "bibcode": "2021GCN.30983....1K",
  "body": "D. A. Kann (HETH/IAA-CSIC), D. B. Malesani (Radboud U. Nijmegen), V. \nD'Elia (ASI/SSDC, INAF/OAR), A. de Ugarte Postigo (HETH,DARK/NBI), A. \nRossi (INAF-OAS) and C. C. Thoene (HETH/IAA-CSIC) report on behalf of \nthe Stargate consortium:\n\nWe observed the field of the short GRB 210919A (Tohuvavohu et al., GCN \n#30846) at late times with FORS2 mounted on the ESO VLT at Cerro Paranal \nObservatory, Chile. We obtained 6 x 90 s exposure each in V, Rc, and Ic, \nand 12 x 68 s in z_special, under excellent conditions (seeing 0\".9 to \n0\".65 from V to z), on October 2.28 UT, 2021, at a midtime of 13.26 days \nafter the GRB.\n\nOur results are in agreement with the LDT/LMI observations obtained by \nO'Connor et al. (GCN #30934). At the position of the potential afterglow \n(Kann et al., GCN #30883, #30884), we do not detect any source. \nCalibrating against three nearby stars from the Pan-STARRS catalog \n(converted to Johnson-Cousins filters for V, Rc, Ic, following the \nLupton transformations, then converted back to AB magnitudes), we derive \nan upper limit of Ic > 25.8 mag, with the V, Rc observations reaching a \ncomparable depth and the z observation being shallower.\n\nThe nearby source reported by O'Connor et al. (GCN #30934) is detected \nin all filters, and we find that it is marginally extended. We measure, \nagain in AB magnitudes, Ic = 23.83 +/- 0.06 mag in an aperture \ncorresponding to the stellar PSF, it being somewhat brighter using a \nlarger aperture. Therefore, this object is a host galaxy candidate for \nGRB 210919A, in agreement with O'Connor et al. (GCN #30934).\n\nAt the eastern edge of the XRT error circle (Goad et al., GCN #30850), \nwe find a further, fainter source at RA = 5:21:01.35, Dec. = +1:18:41.9 \n(J2000) with an error of 0\".5. For this source, we measure Ic = 25.01 \n+/- 0.19 mag. As the source is faint, we can't make any definite \nstatements about its extension. It is also a host galaxy candidate, \nalthough its chance association probability is quite large.",
  "circularId": 30983,
  "createdOn": 1635123118000,
  "email": "kann@iaa.es",
  "subject": "GRB 210919A: FORS2/VLT observations",
  "submitter": "Alexander Kann at IAA-CSIC  <kann@iaa.es>",
  "eventId": "GRB 210919A"
}