Voigt profile fitting of the Ly- absorption feature in the GRB090426 spectrum. Two different components are identified: the first is at z=2.61 and consistent with the other lines, the second is at a different redshift z=2.59. The central tick marks the arbitrary x-axis origin.

Large Binocular Camera Blue & Red Channels image of the host galaxy of GRB 090426 obtained at LBT about 35 days after the burst. The host galaxy of the GRB appears irregular and the core is located 1.4'' S-W from the afterglow position (marked by the two lines). Coincident with the afterglow position (green radius error circle), there is an emitting knot that should be part of the host galaxy. The images were processed by using the LBC reduction pipeline at the LBC Survey Center at the Astronomical Observatory of Rome. The images were calibrated with a subcatalog extracted from the SDSS, by selecting the highest S/N unsaturated objects. LBC fit mosaic to any filter was aligned and resampled at the same pixel grid, then convolved to the a same common seeing; filters were associated wiht RGB channels according to this sequence: red channel as a composition of (z+i)/2 SLOAN filters, green as r SLOAN filter and blue as g SLOAN filter. Resulting fitted images became the input of a rendering colour program (we used STIFF), to examine the input images and create a histogram of pixel values, from which we derive statistics: low and high cuts were determined automatically to optimize the dynamic gamma range using quantile at 95%. The gamma factor is also interpolated for each pixel using a luminance factor of Y=(R+G+B)/3.

Two-dimensional TNG+DOLORES spectrum of GRB 090426.