X-ray plateaus in gamma-ray bursts’ light curves from jets viewed slightly off-axis
Jul 12, 2019
11 pages
Published in:
- Mon.Not.Roy.Astron.Soc. 492 (2020) 2, 2847-2857
- Published: Feb 21, 2020
e-Print:
- 1907.05899 [astro-ph.HE]
DOI:
- 10.1093/mnras/staa070 (publication)
View in:
Citations per year
Abstract: (Oxford University Press)
Using multiple observational arguments, recent work has shown that cosmological gamma-ray bursts (GRBs) are typically viewed at angles within, or close to the cores of their relativistic jets. One of those arguments relied on the lack of tens-of-days-long periods of very shallow evolution that would be seen in the afterglow light curves of GRBs viewed at large angles. Motivated by these results, we consider that GRBs efficiently produce γ-rays only within a narrow region around the core. We show that, on these near-core lines of sight, structured jets naturally produce shallow phases in the X-ray afterglow of GRBs. These plateaus would be seen by a large fraction of observers and would last between 10^2–10^5 s. They naturally reproduce the observed distributions of time-scales and luminosities as well as the intercorrelations between plateau duration, plateau luminosity, and prompt γ-ray energy. An advantage of this interpretation is that it involves no late-time energy injection which would be both challenging from the point of view of the central engine and, as we show here, less natural given the observed correlations between plateau and prompt properties.Note:
- 11 pages, 6 figures. Accepted for publication in MNRAS
- radiation mechanisms: general
- gamma-ray burst: general
References(79)
Figures(10)