TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2440 SUBJECT: GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m DATE: 03/11/07 01:35:40 GMT FROM: Frank Bertoldi at MPIFR/Bonn F. Bertoldi (MPIfR Bonn), D.A. Frail (NRAO), E. Berger (Caltech), K.M. Menten (MPIfR Bonn), S. Kulkarni (Caltech) report: We have imaged a ca. 13 arcmin radius field around the WXM localization of GRB031026 (Butler et al. GCN 2429), using the Max-Planck Millimeter Bolometer array at the IRAM 30m telescope. We do not find any source with a 250 GHz (1.2 mm) flux density >16 mJy (4 sigma upper limit) within 10 armin of this position. The observations were conducted between UT Oct 10.9 and Nov 2.2. Further details and maps can be found at http://www.mpifr-bonn.mpg.de/staff/bertoldi/projects/grb031026 We wish to thank the IRAM staff for their flexibile scheduling of the telescope, which made these observations possible. This result may be cited.