{
  "bibcode": "2005GCN..4044....1D",
  "body": "V. D'Elia, S. Piranomonte, F. Fiore (INAF-OAR), S. Covino (INAF/OABr), \nL.A. Antonelli, G.L. Israel,\nL. Stella, L. Sbordone (INAF-OAR), D. Fugazza,  G. Tagliaferri \n(INAF/OABr), D. Malesani (SISSA), G. Chincarini (Univ. Milano-Bicocca),\non behalf of the MISTICI collaboration, report:\n\n\"Starting on September 22, 2005 23:28:59 UT (~3.5 hours after the GRB\ntrigger) we have obtained high resolution spectra (R~40,000, 7.5 km/s\nin the observer frame) of the optical afterglow of GRB050922C (Krimm et\nal., GCN 4020, Rykoff et al. GCN 4011) using UVES at VLT/Kueyen.  The\nobservations consisted of 2 exposures for a total of 6000 seconds net\nintegration covering the full spectral range 3100-10000 Angstrom, under \ngood seeing conditions. At the time of the observations the afterglow\nmagnitude was R~19-19.5. The resulting continuum signal to noise per\nresolution element spans from 10 to 20 in the 4000-7000 Angstrom\nrange. The afterglow is clearly detected down to ~3300 Angstrom.\nA preliminary analysis of the data shows a very rich spectrum.  We\nfind four main systems at z=2.199, 2.077, 2.008 and 1.9985 (the first\n2 systems have been previously reported by Jakobsson et al., GCN\n4029, and by Piranomonte et al., GCN 4032). The latter two systems are\nshifted by only 950 km/s (rest frame). The strongest absorption lines\nof the four systems are the following.\n\nz=2.199: Lyalpha, Lybeta, OVI1032,1038, SiII1190,1193, SiII1260,\nFeII1260, SiII*1264, SiII*1266, OI1302, SiII1304, OI*1304, OI*1306,\nSiII*1309, CII1334, CII*1335, SiIV1393,1402, SiII*1533, CIV1548,1550,\nFeII1608, FeII*1621, AlII1670, AlIII1862,1854,\nFeII2344,2374,2382,2586,2600, MgII2796,2803\n\nz=2.077: Lyalpha, OI_1302, SiII1304, CII1334, SiIV1393,1402,\nCIV1548,1550, FeII1608, AlII1670, AlIII1854,\nFeII2344,2374,2382,2586,2600\n\nz=2.008 Lyalpha, CIV1548,1550, SiIV1402,1393\n\nz=1.9885 Lyalpha, CIV1548,1550, SiIV1402,1393\n\nTherefore,  fine-structure lines of CII*, SiII*, OI*, FeII*, witnessing\na high density environment, are detected only for the highest redshift\nsystems, likely associated with the GRB host galaxy.\n\nA full analysis is underway.\n\nWe thank Paul Vreeswijk and Poshak Gandhi of the ESO staff for the \nexcellent support in performing these observations in  service mode.\"\n\nThis message can be cited.",
  "circularId": 4044,
  "createdOn": 1127926522000,
  "email": "piranomonte@mporzio.astro.it",
  "subject": "GRB050922C: UVES/VLT high resolution spectroscopy",
  "submitter": "Silvia Piranomonte at OAR  <piranomonte@mporzio.astro.it>",
  "eventId": "GRB 050922C"
}