E_p − L plane for the Swift/eBAT6 sample. The individual data points are colour-coded by redshift; the filled red line represents the E_p − L_iso relation found by Pescalli et al. (2016) for this sample and the dashed red lines represents the scatter. A 2D Gaussian kernel density estimation of the data is shown as grey shaded contours. The black dashed, dot-dashed, and dotted lines represent the detection threshold for and a fixed Band spectrum (α = 0.6, β = 2.5) at redshifts 0.3, 2, and 5, respectively. The side histograms represent the binned data and the colour of each bin represents the median redshift in that bin following the colour-code of the central panel; the black curve is the 1D Gaussian kernel density estimation.