TITLE: GCN CIRCULAR NUMBER: 28914 SUBJECT: Swift Trigger 1006917 is Be/X-ray binary pulsar 1A 0535+262 DATE: 20/11/17 00:33:31 GMT FROM: Kim Page at U.of Leicester N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 00:12:35 UT, the Swift Burst Alert Telescope (BAT) triggered and located 1A 0535+262 (trigger=1006917). Swift slewed immediately to the pulsar. The BAT light curve showed a multi-peaked structure with a duration of about 25 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 00:13:11.5 UT, 35.8 seconds after the BAT trigger, and detected 1A 0535+262. The initial flux in the 0.1 s image was 2.93e-08 erg cm^-2 s^-1 (0.2-10 keV). BAT also triggered on this source several times earlier tonight, between 23:00 and 23:13 UT on November 16 (trigger numbers 1006906, 1006907 and 1006911). All of these triggers occurred during star tracker loss of lock. Because of the star tracker problems, the coordinates provided in the automatic GCN Notices are unreliable.