TITLE: GCN GRB OBSERVATION REPORT NUMBER: 995 SUBJECT: GRB 010222 DATE: 01/02/27 12:56:58 GMT FROM: Michael Bremer at IRAM Grenoble Interferometric Millimeter Observations of GRB 010222 M. Bremer (1), A. Castro-Tirado (2,3) and R. Moreno(1) report: (1) IRAM (Grenoble, France) (2) IAA-CSIC (Granada, Spain) (3) LAEFF-INTA (Madrid, Spain) We have observed the GRB 010222 radio counterpart with the Plateau de Bure Interferometer (PdBI) in a compact five antenna configuration on February 24.94 - 25.11 UT, using the position from Henden et al. (GCN 967). Weather conditions were good for wavelengths of 3mm but marginal for 1mm. The flux calibration was relative to CRL 618 (1.55 Jy at 3mm and 2 Jy at 1mm) and is accurate to about 10%. The source was not detected. UV fits on the phase center give the following upper limits (fit errors are one sigma) : 93.109 GHz : -0.49 +- 0.32 mJy/beam 232.032 GHz : -0.09 +- 1.6 mJy/beam The results have been corrected for atmospheric decorrelation. Synthesized beams were 9.3" x 5.2" at PA -57 degrees and 3.6" by 2.3" at PA -46 degrees, respectively. No bright sources were detected within the primary beam.