TITLE: GCN CIRCULAR NUMBER: 17052 SUBJECT: GRB 141109B: IRAM 30m millimetre observations DATE: 14/11/10 10:16:50 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. J. Castro-Tirado, J. C. Tello (IAA-CSIC Granada), A. Monfardini (NEEL-CNRS Grenoble), R. Adam, B. Comis (LPSC Grenoble), N. Ponthieu (Univ. of Grenoble), C. Kramer and I. Hermelo (IRAM Granada), on behalf of a larger collaboration, report: Following the detection of GRB 141109B by Swift (Melandri et al. GCNC 17038), observations with the IRAM 30m antenna (+NIKA) at Pico Veleta (Spain) were triggered on 9 Nov under good conditions but at relatively low elevation (25 deg). At the position of the X-ray afterglow (Beardmore et al. GCNC 17045), we detect no mm afterglow (at 150 GHz) down to a preliminary flux density of 1 mJy (3 sigma) on Nov 9, 20:30 UT (mid time). We acknowledge excellent assistance from the IRAM observers.