2 2 D ec 2 00 6 GRB 050713 A : High Energy Observations of the GRB Prompt and Afterglow Emission

Swift discovered GRB 050713A and slewed promptly to begin observing with its narrow field instruments 72.6 seconds after the burst onset, while the prompt gamma-ray emission was still detectable in the BAT. Simultaneous emission from two flares is detected in the BAT and XRT. This burst marks just the second time that the BAT and XRT have simultaneously detected emission from a burst and the first time that both instruments have produced a well sampled, simultaneous dataset covering multiple X-ray flares. The temporal rise and decay parameters of the flares are consistent with the internal shock mechanism. In addition to the Swift coverage of GRB 050713A, we report on the Konus-Wind (K-W) detection of the prompt emission, an upper limiting GeV measurement of the prompt emission made by the MAGIC imaging atmospheric Cherenkov telescope and XMM-Newton observations of the afterglow. Simultaneous observations between Swift XRT and XMM-Newton produce consistent results, showing a break in the lightcurve at T0+∼15 ks. Together, these four observatories provide unusually broad spectral coverage of the prompt emission and detailed X-ray follow-up of the afterglow for two weeks after the burst trigger. Simultaneous spectral fits of K-W with BAT and BAT with XRT data indicate that an absorbed broken powerlaw is often a better fit to GRB flares than a simple absorbed powerlaw. Department of Astronomy & Astrophysics, 525 Davey Lab., Pennsylvania State University, University Park, PA 16802, USA; morris@astro.psu.edu NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA Ioffe Physico-Technical Institute Max-Planck-Institut für Physik, München, Germany Dipartimento di Fisica, Università di Siena, and INFN Pisa, Italy Institut de F́ısica d’Altes Energies, Barcelona, Spain Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK