{
  "bibcode": "2022GCN.32595....1S",
  "body": "B. Schneider (CEA Paris-Saclay), D. B. Malesani (Radboud Univ. and DAWN/NBI),\nJ. P. U. Fynbo (DAWN/NBI), K. Wiersema (Univ. Lancaster), L. Izzo (DARK/NBI),\nA. J. Levan (Radboud Univ.) report on behalf of the Stargate collaboration:\n\nWe observed the location of GRB 220611A (Cenko et al., GCN 32191;\nGoad et al., GCN 32192; O���Connor et al., GCN 32203; Rastinejad et al.,\nGCN 32208; Malesani et al., GCN 32222; Levan et al., GCN 32262) using the\nX-shooter spectrograph mounted on the ESO VLT UT3 (Melipal). Our target was\nthe faint object visible in the archival optical images from the Legacy Survey,\ncoincident with the optical and X-ray afterglow, first noticed by\nRastinejad et al. (GCN 32208).\n\nThe observation was performed on 2022 September 23 (104 days after the GRB)\nand consisted of 4x1200 s in the UVB and VIS arms and 8x600 s in the NIR arm.\nA filter was adopted to block part of the K band which in return increases\nthe efficiency of the J and H bands, resulting in a wavelength coverage\nbetween 3000 to 21000 AA.\n\nIn a preliminary reduction, we detect several strong emission lines that\nwe identify as Lyman-alpha, [O II] 3729, [O III] 4959 and [O III] 5007 at a\ncommon redshift of z = 2.3608 +/- 0.0002. The [O II] 3726 and H-beta lines\nare affected by sky lines and are consequently not clearly detected. H-alpha\nfalls outside the covered wavelength range.\n\nThis result is supported by a VLT/MUSE spectrum obtained on 2022 August 24,\ncovering the wavelength range 4800 to 9300 AA, which shows no emission nor\nabsorption features, consistent with the measured redshift from X-shooter.\n\nThe positional coincidence between our target and the optical and X-ray\nafterglow suggests a physical association. Furthermore, our spectra show\nthat the archival counterpart is a star-forming galaxy, akin to a typical\nlong GRB host. Our observations bring thus evidence that the GRB was not\nphysically associated with the local, nearby galaxy MCG-06-10-007 at z = 0.049\n(Cenko et al., GCN 32191), and their proximity is a chance coincidence.\n\nWe acknowledge expert support from the ESO staff in Paranal, in particular\nThomas Rivinius and Michael Abdul-Masih.",
  "circularId": 32595,
  "createdOn": 1664292122000,
  "email": "benjamin.schneider@cea.fr",
  "subject": "GRB 220611A: Host galaxy redshift from VLT/X-shooter",
  "submitter": "Benjamin Schneider at CEA  <benjamin.schneider@cea.fr>",
  "eventId": "GRB 220611A"
}