Notes. For every GRB we list the redshift, z, the properties of the optical SED (spectral slope β_opt, host extinction in the V-band rest frame, , and the corresponding extinction law), the spectral slope in the X-rays, β_x, and the mean time after the burst, t_mid, at which the SED was extracted. The events for which we used joint optical-to-X-ray SEDs are marked with a “†”. In these cases the difference in the spectral slope, β_x − β_opt was either fixed to 1/2 or 0. Except for GRB 080514B, these estimates have only one error estimate for β_opt and β_x together due to the fitting procedure described in the associated papers.

References. (1) Berger & Becker (2005); (2) Kann et al. (2010); (3) de Pasquale et al. (2007); (4) Fynbo et al. (2009); (5) Schady et al. (2010); (6) Piranomonte et al. (2008); (7) Quimby et al. (2005); (8) Soderberg et al. (2006); (9) Kann et al. (2008); (10) Prochaska et al. (2006); (11) Bloom et al. (2006); (12) Della Valle et al. (2006b); (13) Mangano et al. (2007); (14) Jakobsson et al. (2006); (15) Krühler et al. (2008); (16) Thöne et al. (2007); (17) D’Elia et al. (2009); (18) Racusin et al. (2008); (19) Rossi et al. (2009); (20) Krühler et al. (2009); (21) Greiner et al. (2009a); (22) Kuin et al. (2009); (23) de Ugarte Postigo et al. (2009); (24) Cenko et al. (2010); (25) McBreen et al. (2010); (26)  Fatkhullinet al. (2009); (27)  Rau et al. (2010)