TITLE: GCN CIRCULAR NUMBER: 22097 SUBJECT: Fermi GBM detections of Swift J0243.6+6124 and modification of the GBM trigger configuration DATE: 17/11/04 01:26:40 GMT FROM: Michael S. Briggs at UAH and MSFC M. S. Briggs (UAH), C. Wilson-Hodge (MSFC), M. Gibby (Jacobs) and N. Bhat (UAH) report: Fermi GBM began triggering on pulses from the Be X-ray binary Swift J0243.6+6124 (Cenko et al., GCN #21960) on Oct 30th (Bissaldi et al., GCN #22075).  As the source brightened (https://gammaray.nsstc.nasa.gov/gbm/science/pulsars/lightcurves/swiftj0243.html and https://swift.gsfc.nasa.gov/results/transients/weak/SwiftJ0243.6p6124/), the trigger rate increased until there were approximately 40 triggers on Nov 3rd.  To reduce the trigger rate due to this source, the GBM team has disabled some of the onboard trigger algorithms. We expect that there will still be a few triggers per day, which might increase if Swift J0243.6+6124 brightens further.  The GBM team may make further modifications to the onboard trigger configuration and will not issue GCN Circulars to classify individual events from Swift J0243.6+6124 that were misclassified in automatic notices. The ground-based GBM subthreshold transient search (https://gcn.gsfc.nasa.gov/admin/fermi_gbm_subthreshold_announce.txt) has not been modified and will continue to generate GCN Notices due to Swift J0243.6+6124 (Briggs et al., GCN #22047).  There have been more than 1000 detections of this source by the GBM subthreshold search.