1. Interpreting the X-ray afterglows of gamma-ray bursts with radiative losses and millisecond magnetars.
- Author
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Sarin, Nikhil, Lasky, Paul D, and Ashton, Gregory
- Subjects
GAMMA ray bursts ,MAGNETARS ,X-rays - Abstract
The spin-down energy of millisecond magnetars has been invoked to explain X-ray afterglow observations of a significant fraction of short and long gamma-ray bursts. Here, we extend models previously introduced in the literature, incorporating radiative losses with the spin-down of a magnetar central engine through an arbitrary braking index. Combining this with a model for the tail of the prompt emission, we show that our model can better explain the data than millisecond-magnetar models without radiative losses or those that invoke spin-down solely through vacuum dipole radiation. We find that our model predicts a subset of X-ray flares seen in some gamma-ray bursts. We can further explain the diversity of X-ray plateaus by altering the radiative efficiency and measure the braking index of newly born millisecond magnetars. We measure the braking index of GRB061121 as |$n=4.85^{+0.11}_{-0.15}$| suggesting the millisecond-magnetar born in this gamma-ray burst spins down predominantly through gravitational-wave emission. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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