{
  "bibcode": "1999GCN...324....1V",
  "body": "P.M. Vreeswijk, T.J. Galama, E. Rol, B. Stappers (U. of Amsterdam),\nE. Palazzi, E. Pian, N. Masetti, F. Frontera (ITESRE, CNR, Bologna),\nJ. van Paradijs (U. of Amsterdam and U. of Alabama in Huntsville),\nC. Kouveliotou (USRA/MSFC) and H. Boehnhardt (ESO) report on behalf of\nthe Amsterdam/Huntsville and BeppoSAX GRB optical follow-up teams:\n\nThree 10-min red grism and three 10-min blue grism low resolution\nspectra covering 3300-11000 Angstrom, were taken of the optical\ncounterpart to GRB 990510 (Vreeswijk et al.; GCN #310) with the\nEuropean Southern Observatory (ESO) VLT-UT1 telescope, starting May\n11.21 UT. We identified the following ultraviolet absorption lines: \nFe II (2344 and 2600 Angstrom), Mg II (blend of 2796 and 2803). These\nlines are redshifted by z = 1.619 +- 0.002 (this may be a lower limit\nto the redshift of the GRB source). On the basis of this redshift we\nalso find some weaker features, such as Al III (1863), Cr II/Zn II\n(2062), and Mg I (2852). No strong emission lines were detected.\n\nAssuming isotropic emission, z = 1.619, H0 = 70 km/s/Mpc and\nOmega0=0.3, we find a (> 20 keV) energy output of 1.4x10^{53} ergs,\nbased on the BATSE fluence (Kippen et al.; GCN #322).\n\n\nThis message is citeable.",
  "circularId": 324,
  "createdOn": 926628638000,
  "email": "pmv@astro.uva.nl",
  "subject": "VLT spectrum of GRB990510",
  "submitter": "Paul Vreeswijk at U of Amsterdam  <pmv@astro.uva.nl>",
  "eventId": "GRB 990510"
}