{
  "bibcode": "1999GCN...374....1R",
  "body": "E. Rol, P. Vreeswijk, T. Galama (U. of Amsterdam), N. Masetti,\nE. Palazzi, E. Pian, F. Frontera (ITESRE, CNR, Bologna), J. van\nParadijs (U. of Amsterdam and U. of Alabama in Huntsville),\nC. Kouveliotou (USRA/MSFC), R. Strom (NFRA and U. of Amsterdam), G. de\nBruyn (NFRA and U. of Groningen) and T. Augusteijn (ESO) report:\n\nWe have observed the BeppoSAX NFI error circle of GRB 990704 (Gandolfi\n1999, GCN 364) with the Westerbork Synthesis Radio Telescope (WSRT).\nWe observed for 9.2 hours at 4.88 GHz centered on July 5.75 UT, 1999.\nWithin the error circle we detect two sources at 4.88 GHz. Their\nfluxes and positions are given below:\n\n\tflux (mJy)\tRA(J2000)\tDecl.(J2000)\n\n\t 0.68\t\t12:19:27.2\t-03:51:38.5\n\t 0.35\t\t12:19:31.0\t-03:52:05.3\n\nThe error in the flux is 0.065 mJy. The error in the RA and Decl. are\n0.5\" and 5\", respectively.\n\nWe have also observed the error circle in the R band with the ESO 2.2m\n(La Silla) and VLT-UT1 Antu (Paranal) telescopes, 6.5 and 30.5 hours\nafter the burst, respectively. We calibrated these images with the\nLandolt SA104 field (stars 350 and 456; Landolt 1992, AJ, 104, 340).\nWe detect an object at RA 12:19:27.20, Decl. -3:51:39.7 (J2000;\npositional accuracy of about 2\"), coincident with the first radio\nsource.\n\nWe measure the following magnitudes for this object:\n\n        UT Date         R       err.      telescope\n        \n        July 4.96       22.05   0.16      2.2m\n        July 6.01       22.00   0.05      VLT-UT1\n        July 6.07       21.87   0.07      VLT-UT1\n\nThe error in the absolute calibration (estimated to be 0.2 mag.) is\nnot included in the error listed above. The object is constant within\nthe measurement errors and it is therefore not likely the counterpart\nof GRB990704.\n\nAt the position of the second radio source, no object is detected. The\n5 sigma limiting magnitudes of the 2.2m and the co-added VLT-UT1\nimages are R=22.2 and R=23.5, respectively.\n\n\nThis message is citeable.",
  "circularId": 374,
  "createdOn": 931289200000,
  "email": "pmv@astro.uva.nl",
  "subject": "GRB990704 radio and optical observations",
  "submitter": "Paul Vreeswijk at U of Amsterdam  <pmv@astro.uva.nl>",
  "eventId": "GRB 990704"
}