Burst spectral energy distribution and residuals of the first second of burst #4 when fitted by the four used models. Results for other bursts are shown in Fig. A.5. Panel a shows the spectrum, with the continuous blue line representing the NS atmosphere with f_a factor model, the continuous gray line representing the pre-burst emission model shown in Fig. 2, and the gray points representing the data. Panel b shows the residuals for the blackbody model. Panel c shows the residuals for the NS atmosphere model. Panel d shows the residuals for the blackbody with f_a factor model, with magenta for the constant*(diskbb+comptt) case and cyan for constant*diskbb+comptt case, both with square markers. Since their behavior is similar, the magenta markers overlap the cyan ones. Panel e shows the residuals of the NS atmosphere with f_a factor model.