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@Article{GuiriecKDZHNTBGGKMMRRRU:2015:NeMoGR,
               author = "Guiriec, S. and Kouvelitou, C. and Daigne, F. and Zhang, B. and 
                         Hascoet, R. and Nemmen, R. S. and Thompson, D. J. and Bhat, P. N. 
                         and Gehrels, S. and Gonzalez, M. M. and Kaneko, Y. and McEnery, J. 
                         and Mochkovitch, R. and Racusin, J. L. and Ryde, F. and Reyes, 
                         Jos{\'e} Rodrigo Sacahui and Unsal, A. M.",
          affiliation = "NASA and NASA and {} and {} and {} and {} and NASA and {} and NASA 
                         and {} and {} and NASA and {} and NASA and {} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "Toward a better understanding of the GRB phenomenon: a new model 
                         for GRB prompt emission and its effects of the new 
                         L-i(NT)-E-peak,i(rest,NT) relation",
              journal = "Astrophysical Journal",
                 year = "2015",
               volume = "807",
               number = "2",
                month = "July",
             keywords = "acceleration of particles, black hole physics, distance scale, 
                         gamma-ray burst: general, radiation mechanisms: non-thermal, 
                         radiation mechanisms: thermal.",
             abstract = "Gamma-ray burst (GRB) prompt emission spectra in the keV-MeV 
                         energy range are usually considered to be adequately fitted with 
                         the empirical Band function. Recent observations with the Fermi 
                         Gamma-ray Space Telescope (Fermi) revealed deviations from the 
                         Band function, sometimes in the form of an additional blackbody 
                         (BB) component, while on other occasions in the form of an 
                         additional power law (PL) component extending to high energies. In 
                         this article we investigate the possibility that the three 
                         components may be present simultaneously in the prompt emission 
                         spectra of two very bright GRBs (080916C and 090926A) observed 
                         with Fermi, and how the three components may affect the overall 
                         shape of the spectra. While the two GRBs are very different when 
                         fitted to a single Band function, they look like {"}twins{"} in 
                         the three-component scenario. Through fine-time spectroscopy down 
                         to the 100 ms timescale, we follow the evolution of the various 
                         components. We succeed in reducing the number of free parameters 
                         in the three-component model, which results in a new 
                         semi-empirical model-but with physical motivations-to be 
                         competitive with the Band function in terms of number of degrees 
                         of freedom. From this analysis using multiple components, the Band 
                         function is globally the most intense component, although the 
                         additional PL can overpower the others in sharp time structures. 
                         The Band function and the BB component are the most intense at 
                         early times and globally fade across the burst duration. The 
                         additional PL is the most intense component at late time and may 
                         be correlated with the extended high-energy emission observed 
                         thousands of seconds after the burst with Fermi/Large Area 
                         Telescope. Unexpectedly, this analysis also shows that the 
                         additional PL may be present from the very beginning of the burst, 
                         where it may even overpower the other components at low energy. We 
                         investigate the effect of the three components on the new 
                         time-resolved luminosity-hardness relation in both the observer 
                         and rest frames and show that a strong correlation exists between 
                         the flux of the non-thermal Band function and its E-peak only when 
                         the three components are fitted simultaneously to the data (i.e., 
                         F-i(NT)-E-peak,i(NT) relation). In addition, this result points 
                         toward a universal relation between those two quantities when 
                         transposed to the central engine rest frame for all GRBs (i.e., 
                         L-i(NT)-E-peak,i(rest,NT) relation). We discuss a possible 
                         theoretical interpretation of the three spectral components within 
                         this new empirical model. We suggest that (i) the BB component may 
                         be interpreted as the photosphere emission of a magnetized 
                         relativistic outflow, (ii) the Band component has synchrotron 
                         radiation in an optically thin region above the photosphere, 
                         either from internal shocks or magnetic field dissipation, and 
                         (iii) the extra PL component extending to high energies likely has 
                         an inverse Compton origin of some sort, even though its extension 
                         to a much lower energy remains a mystery.",
                  doi = "10.1088/0004-637X/807/2/148",
                  url = "http://dx.doi.org/10.1088/0004-637X/807/2/148",
                 issn = "0004-637X and 1538-4357",
             language = "en",
        urlaccessdate = "04 dez. 2020"
}


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