Zhang, Bin-BinBin-BinZhangBurrows, David N.David N.BurrowsZhang, BingBingZhangStratta, GiuliaGiuliaStrattaD'Elia, ValerioValerioD'Elia2020-09-172020-09-172012-04-01https://hdl.handle.net/20.500.13025/2671The Astrophysical Journal, Volume 748, Issue 2, article id. 132, <NUMPAGES>9</NUMPAGES> pp. (2012).The double burst, GRB 110709B, triggered the Swift/Burst Alert Telescope (BAT) twice at 21 32 39 UT and 21 43 45 UT, respectively, on 2011 July 9. This is the first time we observed a gamma-ray burst (GRB) with two BAT triggers. In this paper, we present simultaneous Swift and Konus-WIND observations of this unusual GRB and its afterglow. If the two events originated from the same physical progenitor, their different time-dependent spectral evolution suggests they must belong to different episodes of the central engine, which may be a magnetar-to-BH accretion system.gamma-ray burst general10.1088/0004-637X/748/2/132http://adsabs.harvard.edu/abs/2012ApJ...748..132Z2012ApJ...748..132Z