! Swift/XRT lightcurve of trigger: 21816, name: GRB 250309B/IceCube-250309A - source 18 ! T0 for this burst is Swift MET=763198746.212 s, = 2025 Mar 09 at 07:38:31.000 UT ! Data covers 0.3-10 keV ! The data are in 5 columns: "; ! time, time error (+ve), time error (-ve), source flux, source error ! For a detailed description of light curve production, see Evans et al. 2007 (A&A, 469, 379 ) ! For a detailed description of the file, see ! http://www.swift.ac.uk/xrt_curves/docs.php ! This lightcurve was obtained from http://www.swift.ac.uk/xrt_curves/00021816 ! BINMODE: GRB-like (counts) READ TERR 1 2