Spectral-Luminosity relation within individual Fermi GRBs - Astrophysics > High Energy Astrophysical PhenomenaReportar como inadecuado




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Abstract: We study the spectra of all long Gamma Ray Bursts GRBs of known redshiftdetected by the Fermi satellite. Their fluxes and fluences are large enough toallow a time dependent study of their spectral characteristics in the 8 keV-1MeV energy range. We find that the peak energy Ep of their ELE spectrumcorrelates with the luminosity in a remarkable tight way within individualbursts. This time resolved Ep-Liso correlation is very similar for all theconsidered bursts, and has a slope and normalisation similar to the analogousEp-Liso correlation defined by the time integrated spectra of different burstsdetected by several different satellites. For a few of the considered GRBs, wecould also study the behaviour of the Ep-Liso correlation during the rising anddecaying phases of individual pulses within each burst, finding no differences.Our results indicate the presence of a similar physical mechanism, operatingfor the duration of different GRBs, linking tightly the burst luminosity withthe peak energy of the spectrum emitted at different times. Such a physicalmechanism is the same during the rise and decay phase of individual pulsescomposing a GRB. These results, while calling for a robust physicalinterpretation, strongly indicate that the Ep-Liso spectral energy correlationfound considering the time integrated spectra of different bursts is real, andnot the result of instrumental selection effects.



Autor: G. Ghirlanda 1, L. Nava 1,2, G. Ghisellini 1 1INAF-Osservatorio Astronomico di Brera, 2Universita' dell'Insubria

Fuente: https://arxiv.org/







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