Multiwavelength Analysis of the Intriguing GRB 061126: The Reverse Shock Scenario and Magnetization
We present a detailed study of the prompt and afterglow emission from Swift GRB 061126 using BAT, XRT,UVOT data and multicolor optical imaging from 10 ground-based telescopes. GRB 061126 was a long burst(T90 ¼ 191 s) with four overlapping peaks in its -ray light curve. The X-ray afterglow, observed...
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Institute of Physics Publishing, Inc.
2008
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| Online Access: | http://iopscience.iop.org/0004-637X/687/1/443/pdf/74449.web.pdf http://hdl.handle.net/20.500.11937/39783 |
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| author | Gomboc, A. Kobayashi, S. Guidorzi, C. Melandri, A. Mangano, V. Sbarufatti, B. Mundell, C. Schady, P. Smith, R. Updike, A. Kann, D. Misra, K. Rol, E. Pozanenko, A. Castro-Tirado, A. Anupama, G. Bersier, D. Bode, M. Carter, D. Curran, Peter Fruchter, A. Graham, J. Hartmann, D. Ibrahimov, M. Levan, A. Monfardini, A. Mottram, C. O’Brien, P. Prema, P. Sahu, D. Steele, I. Tanvir, N. Wiersema, K. |
| author_facet | Gomboc, A. Kobayashi, S. Guidorzi, C. Melandri, A. Mangano, V. Sbarufatti, B. Mundell, C. Schady, P. Smith, R. Updike, A. Kann, D. Misra, K. Rol, E. Pozanenko, A. Castro-Tirado, A. Anupama, G. Bersier, D. Bode, M. Carter, D. Curran, Peter Fruchter, A. Graham, J. Hartmann, D. Ibrahimov, M. Levan, A. Monfardini, A. Mottram, C. O’Brien, P. Prema, P. Sahu, D. Steele, I. Tanvir, N. Wiersema, K. |
| author_sort | Gomboc, A. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We present a detailed study of the prompt and afterglow emission from Swift GRB 061126 using BAT, XRT,UVOT data and multicolor optical imaging from 10 ground-based telescopes. GRB 061126 was a long burst(T90 ¼ 191 s) with four overlapping peaks in its -ray light curve. The X-ray afterglow, observed from 26 minutes to20 days after the burst, shows a simple power-law decay with X ¼ 1:290 0:008. Optical observations presentedhere cover the time range from 258 s (Faulkes Telescope North) to 15 days (Gemini North) after the burst; the decayrate of the optical afterglow shows a steep-to-shallow transition (from 1 ¼ 1:48 0:06 to 2 ¼ 0:88 0:03) approximately13 minutes after the burst.We suggest the early, steep component is due to a reverse shock and show thatthe magnetic energy density in the ejecta, expressed as a fraction of the equipartition value, is a few 10 times largerthan in the forward shock in the early afterglow phase. The ejecta might be endowed with primordial magnetic fieldsat the central engine. The optical light curve implies a late-time break at about 1.5 days after the burst, while there is noevidence of the simultaneous break in the X-ray light curve. We model the broadband emission and show that someafterglow characteristics (the steeper decay in X-ray and the shallow spectral index from optical to X-ray) are difficultto explain in the framework of the standard fireball model. This might imply that the X-ray afterglow is due to anadditional emission process, such as late-time central engine activity rather than blast-wave shock emission. Thepossible chromatic break at 1.5 days after the burst would give support to the additional emission scenario. |
| first_indexed | 2025-11-14T09:00:15Z |
| format | Journal Article |
| id | curtin-20.500.11937-39783 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:00:15Z |
| publishDate | 2008 |
| publisher | Institute of Physics Publishing, Inc. |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-397832017-02-28T01:45:24Z Multiwavelength Analysis of the Intriguing GRB 061126: The Reverse Shock Scenario and Magnetization Gomboc, A. Kobayashi, S. Guidorzi, C. Melandri, A. Mangano, V. Sbarufatti, B. Mundell, C. Schady, P. Smith, R. Updike, A. Kann, D. Misra, K. Rol, E. Pozanenko, A. Castro-Tirado, A. Anupama, G. Bersier, D. Bode, M. Carter, D. Curran, Peter Fruchter, A. Graham, J. Hartmann, D. Ibrahimov, M. Levan, A. Monfardini, A. Mottram, C. O’Brien, P. Prema, P. Sahu, D. Steele, I. Tanvir, N. Wiersema, K. cosmology: observations gamma rays: bursts We present a detailed study of the prompt and afterglow emission from Swift GRB 061126 using BAT, XRT,UVOT data and multicolor optical imaging from 10 ground-based telescopes. GRB 061126 was a long burst(T90 ¼ 191 s) with four overlapping peaks in its -ray light curve. The X-ray afterglow, observed from 26 minutes to20 days after the burst, shows a simple power-law decay with X ¼ 1:290 0:008. Optical observations presentedhere cover the time range from 258 s (Faulkes Telescope North) to 15 days (Gemini North) after the burst; the decayrate of the optical afterglow shows a steep-to-shallow transition (from 1 ¼ 1:48 0:06 to 2 ¼ 0:88 0:03) approximately13 minutes after the burst.We suggest the early, steep component is due to a reverse shock and show thatthe magnetic energy density in the ejecta, expressed as a fraction of the equipartition value, is a few 10 times largerthan in the forward shock in the early afterglow phase. The ejecta might be endowed with primordial magnetic fieldsat the central engine. The optical light curve implies a late-time break at about 1.5 days after the burst, while there is noevidence of the simultaneous break in the X-ray light curve. We model the broadband emission and show that someafterglow characteristics (the steeper decay in X-ray and the shallow spectral index from optical to X-ray) are difficultto explain in the framework of the standard fireball model. This might imply that the X-ray afterglow is due to anadditional emission process, such as late-time central engine activity rather than blast-wave shock emission. Thepossible chromatic break at 1.5 days after the burst would give support to the additional emission scenario. 2008 Journal Article http://hdl.handle.net/20.500.11937/39783 http://iopscience.iop.org/0004-637X/687/1/443/pdf/74449.web.pdf Institute of Physics Publishing, Inc. restricted |
| spellingShingle | cosmology: observations gamma rays: bursts Gomboc, A. Kobayashi, S. Guidorzi, C. Melandri, A. Mangano, V. Sbarufatti, B. Mundell, C. Schady, P. Smith, R. Updike, A. Kann, D. Misra, K. Rol, E. Pozanenko, A. Castro-Tirado, A. Anupama, G. Bersier, D. Bode, M. Carter, D. Curran, Peter Fruchter, A. Graham, J. Hartmann, D. Ibrahimov, M. Levan, A. Monfardini, A. Mottram, C. O’Brien, P. Prema, P. Sahu, D. Steele, I. Tanvir, N. Wiersema, K. Multiwavelength Analysis of the Intriguing GRB 061126: The Reverse Shock Scenario and Magnetization |
| title | Multiwavelength Analysis of the Intriguing GRB 061126: The Reverse Shock Scenario and Magnetization |
| title_full | Multiwavelength Analysis of the Intriguing GRB 061126: The Reverse Shock Scenario and Magnetization |
| title_fullStr | Multiwavelength Analysis of the Intriguing GRB 061126: The Reverse Shock Scenario and Magnetization |
| title_full_unstemmed | Multiwavelength Analysis of the Intriguing GRB 061126: The Reverse Shock Scenario and Magnetization |
| title_short | Multiwavelength Analysis of the Intriguing GRB 061126: The Reverse Shock Scenario and Magnetization |
| title_sort | multiwavelength analysis of the intriguing grb 061126: the reverse shock scenario and magnetization |
| topic | cosmology: observations gamma rays: bursts |
| url | http://iopscience.iop.org/0004-637X/687/1/443/pdf/74449.web.pdf http://hdl.handle.net/20.500.11937/39783 |