Understanding the origin and diversity of emission processes responsible for gamma-ray bursts (GRBs) remains a pressing challenge. While prompt and contemporaneous panchromatic observations have the potential to test predictions of the internal-external shock model, extensive multiband imaging has been conducted for only a few GRBs. We present rich, early-time, multiband data sets for two Swift events, GRB 110205A and GRB 110213A. The former shows optical emission since the early stages of the prompt phase, followed by the steep rising in flux up to 1000s after the burst (t -α with α = -6.13 ± 0.75). We discuss this feature in the context of the reverse-shock scenario and interpret the following single power-law decay as being forward-shock dominated. Polarization measurements, obtained with the RINGO2 instrument mounted on the Liverpool Telescope, also provide hints on the nature of the emitting ejecta. The latter event, instead, displays a very peculiar optical to near-infrared light curve, with two achromatic peaks. In this case, while the first peak is probably due to the onset of the afterglow, we interpret the second peak to be produced by newly injected material, signifying a late-time activity of the central engine. © 2011. The American Astronomical Society. All rights reserved.

Cucchiara, A., Cenko, S., Bloom, J., Melandri, A., Morgan, A., Kobayashi, S., et al. (2011). Constraining gamma-ray burst emission physics with extensive early-time, multiband follow-up. THE ASTROPHYSICAL JOURNAL, 743(2), 154 [10.1088/0004-637X/743/2/154].

Constraining gamma-ray burst emission physics with extensive early-time, multiband follow-up

Fumagalli M.;
2011

Abstract

Understanding the origin and diversity of emission processes responsible for gamma-ray bursts (GRBs) remains a pressing challenge. While prompt and contemporaneous panchromatic observations have the potential to test predictions of the internal-external shock model, extensive multiband imaging has been conducted for only a few GRBs. We present rich, early-time, multiband data sets for two Swift events, GRB 110205A and GRB 110213A. The former shows optical emission since the early stages of the prompt phase, followed by the steep rising in flux up to 1000s after the burst (t -α with α = -6.13 ± 0.75). We discuss this feature in the context of the reverse-shock scenario and interpret the following single power-law decay as being forward-shock dominated. Polarization measurements, obtained with the RINGO2 instrument mounted on the Liverpool Telescope, also provide hints on the nature of the emitting ejecta. The latter event, instead, displays a very peculiar optical to near-infrared light curve, with two achromatic peaks. In this case, while the first peak is probably due to the onset of the afterglow, we interpret the second peak to be produced by newly injected material, signifying a late-time activity of the central engine. © 2011. The American Astronomical Society. All rights reserved.
Si
Articolo in rivista - Articolo scientifico
Scientifica
gamma-ray burst: individual (GRB 110205A, GRB 110213A); techniques: photometric; techniques: polarimetric; techniques: spectroscopic
English
154
Cucchiara, A., Cenko, S., Bloom, J., Melandri, A., Morgan, A., Kobayashi, S., et al. (2011). Constraining gamma-ray burst emission physics with extensive early-time, multiband follow-up. THE ASTROPHYSICAL JOURNAL, 743(2), 154 [10.1088/0004-637X/743/2/154].
Cucchiara, A; Cenko, S; Bloom, J; Melandri, A; Morgan, A; Kobayashi, S; Smith, R; Perley, D; Li, W; Hora, J; Da Silva, R; Prochaska, J; Milne, P; Butler, N; Cobb, B; Worseck, G; Mundell, C; Steele, I; Filippenko, A; Fumagalli, M; Klein, C; Stephens, A; Bluck, A; Mason, R
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10281/295234
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