{
  "bibcode": "2002GCN..1633....1S",
  "body": "S. Savaglio (INAF-OAR and JHU), F. Fiore, G. Israel, G. Marconi,\nL.A. Antonelli, A. Fontana, L. Stella, A. Di Paola, G. Stratta (INAF-OAR),\nS. Covino, G. Chincarini, G. Ghisellini, P. Saracco, F. Zerbi (INAF-OABrera),\nD. Lazzati (Cambridge, UK), R. Perna (CfA), M. Vietri (Univ. Roma Tre),\nF. Frontera (Univ. di Ferrara), S. Mereghetti (CNR-IASF),\nE.J.A. Meurs (Dunsink Obs.) and N. Kawai (Titech, RIKEN) report:\n\n\"Starting on October 05 2002 01:37 UT we have obtained high resolution\nspectra (R=50,000, 6 km/s in the observer frame) of the optical\nafterglow of GRB021004 (Fox et al., GCN #1564) using UVES at VLT.  The\nobservations cover the full spectral range 3200-9800 Angstrom, in good\nseeing conditions. At the time of the observations the afterglow\nmagnitude was R~18.6 and B~19.0.\n\nA preliminary analysis of the first hour of observation reveals\nseveral absorption lines associated with at least 4 metal systems\n(also see Salamanca et al., GCN #1611).\n\nThe z=2.321,2.327 system is probably very close to the GRB itself or\nthe circumburst medium. C IV absorption lines associated with this\nsystem are in fact extremely strong and complex, spanning a velocity\nrange of about 1000 km/s. This system may show the so called \"line\nlocking\", possibly relativistic, effect, where the second component of\nthe z=2.321 C IV doublet is \"locked\" to the first component of the\nz=2.327 C IV doublet. This effect has been observed in the past in\nnarrow absorption systems associated with high redshift quasars (e.g.\nWampler 1991, ApJ, 368, 40) and O stars (Lucy & Solomon, 1970, ApJ,\n159, 879).\n\nLow ionization lines of AlII1670 and possibly SiII1526 are also\ndetected in the red wing of the z=2.327 component. Low ionization\nlines are not detected in the lower redshift system at z=2.321.\n\nThe z=2.2958,2.2985 system is shifted by ~2500 km/s blueward of the\nstrong z=2.321,2.327 system and shows much weaker, but still very\nstrong, C IV lines and no low ionization lines. The velocity range of\nthis absorption is of about 300 km/s.\n\nThe z=1.6019 intervening system shows a narrow Al III absorption with\ncolumn density of log N(AlIII)=13.2 +\\- 0.1 and Doppler parameter b=12\n+\\- 1 km/s.\n\nThe other system at z=1.38 shows a complex structure with at least 4\ncomponents spanning a velocity range of about 200 km/s.  The FeII\ncolumn densities suggest that this system may be associated with a\nDamped Lyman Alpha system in the interstellar medium of an intervening\ngalaxy.\"\n\nThis message may be cited.",
  "circularId": 1633,
  "createdOn": 1034605823000,
  "email": "angelo@coma.mporzio.astro.it",
  "subject": "GRB021004: High-resolution optical spectroscopy",
  "submitter": "Angelo Antonelli at Obs. Astro. di Roma  <angelo@coma.mporzio.astro.it>",
  "eventId": "GRB 021004"
}