%0 Journal Article
%T Quantum-Spacetime Scenarios and Soft Spectral Lags of the Remarkable GRB130427A
%A Giovanni Amelino-Camelia
%A Fabrizio Fiore
%A Dafne Guetta
%A Simonetta Puccetti
%J Advances in High Energy Physics
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/597384
%X We process the Fermi LAT data on GRB130427A using the Fermi Science Tools, and we summarize some of the key facts that render this observation truly remarkable. We then perform a search of spectral lags, of the type that has been of interest for its relevance in quantum-spacetime research. We do find some evidence of systematic soft spectral lags: when confining the analysis to photons of energies greater than 5£¿GeV there is an early hard development of minibursts within the burst. The effect is well characterized by a linear dependence, within such a miniburst, of the detection time on energy. We also observe that some support for these features is noticeable also in earlier Fermi-LAT GRBs. Some aspects of the comparison of these features for GRBs at different redshifts could be described within a quantum-spacetime picture, but taking into account results previously obtained by other studies we favour the interpretation as intrinsic properties of GRBs. Even if our spectral lags do turn out to have astrophysical origin their understanding will be important for quantum-spacetime research, since any attempt to reveal minute quantum-spacetime-induced spectral lags evidently requires a good understanding of intrinsic mechanisms at the sources that can produce spectral lags. 1. Introduction and Motivation The study of Gamma-Ray Bursts (GRBs) has been for some time one of the main themes of astrophysics research, and over the last 15 years it became also of interest for research on quantum gravity. These more recent developments look at GRBs as signals and hope to decode properties of quantum-spacetime from the implications of spacetime quantization for how such signals propagate from the distant source to our telescope. Even tiny quantum-spacetime effects modifying the structure of the signal could cumulate along the way, as the signal travels over cosmological distances. As we here contribute to assess, the remarkable very recent observation of GRB130427A is bound to teach us a lot about the astrophysics of GRBs and has the potential to also empower some of the quantum-spacetime studies of GRBs. This GRB130427A was extremely powerful, also thanks to the fact that it was among the nearest long GRBs observed. We here take the perspective that GRB130427A is an opportunity to look at a long GRB in ¡°high resolution,¡± allowing us to notice features which could not be noticed in previous GRBs. In this study we test the potentialities of using GRB130427A in this way by focusing on a much studied class of effects, involving spectral lags with a linear dependence on
%U http://www.hindawi.com/journals/ahep/2014/597384/