Search: WFRF:(Wang Mei Qing)
> (2015) >
HOW BAD OR GOOD ARE...
HOW BAD OR GOOD ARE THE EXTERNAL FORWARD SHOCK AFTERGLOW MODELS OF GAMMA-RAY BURSTS?
-
Wang, Xiang-Gao (author)
-
Zhang, Bing (author)
-
Liang, En-Wei (author)
-
show more...
-
Gao, He (author)
-
- Li, Liang (author)
- Stockholms universitet,Fysikum
-
Deng, Can-Min (author)
-
Qin, Song-Mei (author)
-
Tang, Qing-Wen (author)
-
Kann, D. Alexander (author)
-
- Ryde, Felix (author)
- KTH,Partikel- och astropartikelfysik
-
Kumar, Pawan (author)
-
show less...
-
(creator_code:org_t)
- 2015-07-16
- 2015
- English.
-
In: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 219:1
- Related links:
-
https://repositories...
-
show more...
-
https://arxiv.org/ab...
-
https://urn.kb.se/re...
-
https://doi.org/10.1...
-
https://urn.kb.se/re...
-
show less...
Abstract
Subject headings
Close
- The external forward shock models have been the standard paradigm to interpret the broadband afterglow data of gamma-ray bursts (GRBs). One prediction of the models is that some afterglow temporal breaks at different energy bands should be achromatic; that is, the break times should be the same in different frequencies. Multiwavelength observations in the Swift era have revealed chromatic afterglow behaviors at least in some GRBs, casting doubts on the external forward shock origin of GRB afterglows. In this paper, using a large sample of GRBs with both X-ray and optical afterglow data, we perform a systematic study to address the question: how bad or good are the external forward shock models? Our sample includes 85 GRBs up to 2014 March with well-monitored X-ray and optical light curves. Based on how well the data abide by the external forward shock models, we categorize them into five grades and three samples. The first two grades (Grade I and II) include 45 of 85 GRBs. They show evidence of, or are consistent with having, an achromatic break. The temporal and spectral behaviors in each afterglow segment are consistent with the predictions (the "closure relations") of the forward shock models. These GRBs are included in the Gold sample. The next two grades (Grade III and IV) include 37 of 85 GRBs. They are also consistent with having an achromatic break, even though one or more afterglow segments do not comply with the closure relations. These GRBs are included in the Silver sample. Finally, Grade V (3/85) shows direct evidence of chromatic behaviors, suggesting that the external shock models are inconsistent with the data. These are included in the Bad sample. We further perform statistical analyses of various observational properties (temporal index alpha, spectral index beta, break time t(b)) and model parameters (energy injection index q, electron spectral index p, jet opening angle theta(j), radiative efficiency eta(gamma), and so on) of the GRBs in the Gold sample, and derive constraints on the magnetization parameter epsilon(B) in the forward shock. Overall, we conclude that the simplest external forward shock models can account for the multiwavelength afterglow data of at least half of the GRBs. When more advanced modeling (e.g., long-lasting reverse shock, structured jets, arbitrary circumburst medium density profile) is invoked, up to >90% of the afterglows may be interpreted within the framework of the external shock models.
Subject headings
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Publication and Content Type
- ref (subject category)
- art (subject category)
Find in a library
To the university's database
- By the author/editor
-
Wang, Xiang-Gao
-
Zhang, Bing
-
Liang, En-Wei
-
Gao, He
-
Li, Liang
-
Deng, Can-Min
-
show more...
-
Qin, Song-Mei
-
Tang, Qing-Wen
-
Kann, D. Alexand ...
-
Ryde, Felix
-
Kumar, Pawan
-
show less...
- About the subject
-
- NATURAL SCIENCES
-
NATURAL SCIENCES
-
and Physical Science ...
- Articles in the publication
-
Astrophysical Jo ...
- By the university
-
Royal Institute of Technology
-
Stockholm University