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Multiwavelength Vie...
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- We monitored the position of the close-by (about 370 Mpc) gamma-ray burst GRB 190829A, which originated from a massive star collapse, through very long baseline interferometry (VLBI) observations with the European VLBI Network and the Very Long Baseline Array, carrying out a total of nine observations between 9 and 117 days after the gamma-ray burst at 5 and 15 GHz, with a typical resolution of a few milliarcseconds. From a state-of-the art analysis of these data, we obtained valuable limits on the source size and expansion rate. The limits are in agreement with the size evolution entailed by a detailed modeling of the multiwavelength light curves with a forward-plus-reverse shock model, which agrees with the observations across almost 18 orders of magnitude in frequency (including the HESS data at TeV photon energies) and more than 4 orders of magnitude in time. Thanks to the multiwavelength, high-cadence coverage of the afterglow, inherent degeneracies in the afterglow model are broken to a large extent, allowing us to capture some unique physical insights; we find a low prompt emission efficiency of less than or similar to 10(-3), a low fraction of relativistic electrons in the forward shock downstream chi ( e ) < 13% (90% credible level), and a rapid decay of the magnetic field in the reverse shock downstream after the shock crossing. While our model assumes an on-axis jet, our VLBI astrometry is not sufficiently tight as to exclude any off-axis viewing angle, but we can exclude the line of sight to have been more than similar to 2 degrees away from the border of the gamma-ray-producing region based on compactness arguments.
Ämnesord
- NATURVETENSKAP -- Fysik -- Acceleratorfysik och instrumentering (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Accelerator Physics and Instrumentation (hsv//eng)
- NATURVETENSKAP -- Fysik -- Subatomär fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Subatomic Physics (hsv//eng)
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
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Salafia, Om Shar ...
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Ravasio, Maria E ...
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Yang, Jun, 1979
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An, Tao
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Orienti, Monica
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Ghirlanda, Gianc ...
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visa fler...
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Nava, Lara
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Giroletti, M.
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Mohan, Prashanth
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Spinelli, Riccar ...
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Zhang, Yingkang
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Marcote, Benito
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Cimo, Giuseppe
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Wu, Xuefeng
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Li, Zhixuan
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visa färre...
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- NATURVETENSKAP
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NATURVETENSKAP
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och Fysik
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och Acceleratorfysik ...
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- NATURVETENSKAP
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NATURVETENSKAP
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och Fysik
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och Subatomär fysik
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- NATURVETENSKAP
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NATURVETENSKAP
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och Astronomi astrof ...
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Astrophysical Jo ...
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Chalmers tekniska högskola