Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12386/27083
Title: | Swift and Fermi Observations of X-Ray Flares: The Case of Late Internal Shock | Authors: | Troja, E. PIRO, LUIGI Vasileiou, V. Omodei, N. Burgess, J. M. Cutini, S. Connaughton, V. McEnery, J. E. |
Issue Date: | 2015 | Journal: | THE ASTROPHYSICAL JOURNAL | Number: | 803 | Issue: | 1 | First Page: | 10 | Abstract: | Simultaneous Swift and Fermi observations of gamma-ray bursts (GRBs) offer a unique broadband view of their afterglow emission, spanning more than 10 decades in energy. We present the sample of X-ray flares observed by both Swift and Fermi during the first three years of Fermi operations. While bright in the X-ray band, X-ray flares are often undetected at lower (optical), and higher (MeV to GeV) energies. We show that this disfavors synchrotron self-Compton processes as the origin of the observed X-ray emission. We compare the broadband properties of X-ray flares with the standard late internal shock model, and find that in this scenario, X-ray flares can be produced by a late-time relativistic (Γ > 50) outflow at radii R ~ 10<SUP>13</SUP>-10<SUP>14</SUP> cm. This conclusion holds only if the variability timescale is significantly shorter than the observed flare duration, and implies that X-ray flares can directly probe the activity of the GRB central engine. | URI: | http://hdl.handle.net/20.500.12386/27083 | URL: | https://iopscience.iop.org/article/10.1088/0004-637X/803/1/10 | ISSN: | 0004-637X | DOI: | 10.1088/0004-637X/803/1/10 | Bibcode ADS: | 2015ApJ...803...10T | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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Troja_2015_ApJ_803_10.pdf | Pdf editoriale | 606.82 kB | Adobe PDF | View/Open |
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