TITLE: GCN CIRCULAR NUMBER: 22120 SUBJECT: FACT follow-up of IceCube20171106 DATE: 17/11/13 22:39:06 GMT FROM: Daniela Dorner at U of Wuerzburg A. Biland (ETH Zurich) reports on behalf of the FACT collaboration: On Mon 06 Nov 17 18:40:24 UTC, the IceCube collaboration reported the detection of a high-energy neutrino (run number 130214, event number 17569642). The alert was followed up by MASTER (GCN #22104), INTEGRAL (GCN #22109), HAWC (GCN #22114)and Swift (GCN #22115). An updated position was communicate by IceCube on 17/11/06 22:37:07 GMT (GCN #22105). FACT observed the first position on 2017-11-06 for 3.26 hours and the updated position from 2017-11-07 to 2017-11-11 for 15.64 hours. The automatic Quick Look Analysis (http://www.fact-project.org/monitoring) does not show any significant signal from the observed position. The observations in several nights were affected by bad weather. After data quality selection, an ontime of 6.0 hours remains covering a zenith distance range from 21 degree to 56 degree. Based on these data, an upper limit of 35% of the flux of the Crab Nebula above 750 GeV with a confidence level of 99% has been determined. Contact person: Daniela Dorner (dorner@astro.uni-wuerzburg.de) The First G-APD Cherenkov Telescope (FACT) is an imaging air Cherenkov telescope monitoring at TeV energies. It is located in the Observatorio del Roque de los Muchachos on the Canary Island La Palma.