GRB 200612A: An Ultralong Gamma-Ray Burst Powered by Magnetar Spinning Down

GRB 200612A could be classified as an ultralong gamma-ray burst due to its prompt emission lasting up to ∼1020 s and the true timescale of the central engine activity t burst ≥ 4 × 10 4 s. The late X-ray light curve with a decay index of α = 7.53 is steeper than the steepest possible decay from an e...

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Bibliographic Details
Published in:Research in astronomy and astrophysics 2024-02, Vol.24 (2), p.25017
Main Authors: Chen, Liang-Jun, Wang, Xiang-Gao, Yang, De-Long, Liang, En-Wei
Format: Article
Language:English
Subjects:
(stars:) gamma-ray burst: general
(stars:) gamma-ray burst: individual (GRB 200612A)
Afterglows
Black holes
Decay
Gamma ray astronomy
Gamma ray bursts
Gamma rays
Light curve
Magnetars
stars: magnetars
X-rays
Citations: Items that this one cites
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Summary:GRB 200612A could be classified as an ultralong gamma-ray burst due to its prompt emission lasting up to ∼1020 s and the true timescale of the central engine activity t burst ≥ 4 × 10 4 s. The late X-ray light curve with a decay index of α = 7.53 is steeper than the steepest possible decay from an external shock model. We propose that this X-ray afterglow can be driven by dipolar radiation from the magnetar spindown during its early stage, while the magnetar collapsed into the black hole before its spindown, resulting in a very steep decay of the late X-ray light curve. The optical data show that the light curve is still rising after 1.1 ks, suggesting a late onset. We show that GRB 200612A’s optical afterglow light curve is fitted with the forward shock model by Gaussian structured off-axis jet. This is a special case among GRBs, as it may be an ultralong gamma-ray burst powered by a magnetar in an off-axis observation scenario.
ISSN:1674-4527
2397-6209
DOI:10.1088/1674-4527/ad1d2a