Radio observations of GRB 100418a: Test of an energy injection model explaining long-lasting GRB afterglows

We present the results of our radio observational campaign of gamma-ray burst (GRB) 100418a, for which we used the Australia Telescope Compact Array, the Very Large Array, and the Very Long Baseline Array. GRB 100418a was a peculiar GRB with unusual X-ray and optical afterglow profiles featuring a p...

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Main Authors: Moin, A., Chandra, P., Miller-Jones, James, Tingay, Steven, Taylor, G., Frail, D., Wang, Z., Reynolds, Cormac, Phillips, C.
Format: Journal Article
Published: Institute of Physics Publishing, Inc. 2013
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/42051
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author Moin, A.
Chandra, P.
Miller-Jones, James
Tingay, Steven
Taylor, G.
Frail, D.
Wang, Z.
Reynolds, Cormac
Phillips, C.
author_facet Moin, A.
Chandra, P.
Miller-Jones, James
Tingay, Steven
Taylor, G.
Frail, D.
Wang, Z.
Reynolds, Cormac
Phillips, C.
author_sort Moin, A.
building Curtin Institutional Repository
collection Online Access
description We present the results of our radio observational campaign of gamma-ray burst (GRB) 100418a, for which we used the Australia Telescope Compact Array, the Very Large Array, and the Very Long Baseline Array. GRB 100418a was a peculiar GRB with unusual X-ray and optical afterglow profiles featuring a plateau phase with a very shallow rise. This observed plateau phase was believed to be due to a continued energy injection mechanism that powered the forward shock, giving rise to an unusual and long-lasting afterglow. The radio afterglow of GRB 100418a was detectable several weeks after the prompt emission. We conducted long-term monitoring observations of the afterglow and attempted to test the energy injection model advocating that the continuous energy injection is due to shells of material moving at a wide range of Lorentz factors. We obtained an upper limit of γ < 7 for the expansion rate of the GRB 100418a radio afterglow, indicating that the range-of-Lorentz factor model could only be applicable for relatively slow-moving ejecta. A preferred explanation could be that continued activity of the central engine may have powered the long-lasting afterglow.
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institution Curtin University Malaysia
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publishDate 2013
publisher Institute of Physics Publishing, Inc.
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spelling curtin-20.500.11937-420512017-09-13T14:19:38Z Radio observations of GRB 100418a: Test of an energy injection model explaining long-lasting GRB afterglows Moin, A. Chandra, P. Miller-Jones, James Tingay, Steven Taylor, G. Frail, D. Wang, Z. Reynolds, Cormac Phillips, C. radio continuum: general radiation mechanisms: non-thermal gamma-ray burst: individual (GRB 100418a) relativistic processes outflows stars: winds We present the results of our radio observational campaign of gamma-ray burst (GRB) 100418a, for which we used the Australia Telescope Compact Array, the Very Large Array, and the Very Long Baseline Array. GRB 100418a was a peculiar GRB with unusual X-ray and optical afterglow profiles featuring a plateau phase with a very shallow rise. This observed plateau phase was believed to be due to a continued energy injection mechanism that powered the forward shock, giving rise to an unusual and long-lasting afterglow. The radio afterglow of GRB 100418a was detectable several weeks after the prompt emission. We conducted long-term monitoring observations of the afterglow and attempted to test the energy injection model advocating that the continuous energy injection is due to shells of material moving at a wide range of Lorentz factors. We obtained an upper limit of γ < 7 for the expansion rate of the GRB 100418a radio afterglow, indicating that the range-of-Lorentz factor model could only be applicable for relatively slow-moving ejecta. A preferred explanation could be that continued activity of the central engine may have powered the long-lasting afterglow. 2013 Journal Article http://hdl.handle.net/20.500.11937/42051 10.1088/0004-637X/779/2/105 Institute of Physics Publishing, Inc. fulltext
spellingShingle radio continuum: general
radiation mechanisms: non-thermal
gamma-ray burst: individual (GRB 100418a)
relativistic processes
outflows
stars: winds
Moin, A.
Chandra, P.
Miller-Jones, James
Tingay, Steven
Taylor, G.
Frail, D.
Wang, Z.
Reynolds, Cormac
Phillips, C.
Radio observations of GRB 100418a: Test of an energy injection model explaining long-lasting GRB afterglows
title Radio observations of GRB 100418a: Test of an energy injection model explaining long-lasting GRB afterglows
title_full Radio observations of GRB 100418a: Test of an energy injection model explaining long-lasting GRB afterglows
title_fullStr Radio observations of GRB 100418a: Test of an energy injection model explaining long-lasting GRB afterglows
title_full_unstemmed Radio observations of GRB 100418a: Test of an energy injection model explaining long-lasting GRB afterglows
title_short Radio observations of GRB 100418a: Test of an energy injection model explaining long-lasting GRB afterglows
title_sort radio observations of grb 100418a: test of an energy injection model explaining long-lasting grb afterglows
topic radio continuum: general
radiation mechanisms: non-thermal
gamma-ray burst: individual (GRB 100418a)
relativistic processes
outflows
stars: winds
url http://hdl.handle.net/20.500.11937/42051