On the afterglow from the receding jet of gamma-ray burst

Abstract

According to popular progenitor models of gamma-ray bursts, twin jets should be launched by the central engine, with a forward jet moving toward the observer and a receding jet (or the counter jet) moving backwardly. However, in calculating the afterglows, usually only the emission from the forward jet is considered. Here we present a detailed numerical study on the afterglow from the receding jet. Our calculation is based on a generic dynamical description, and includes some delicate ingredients such as the effect of the equal arrival time surface. It is found that the emission from the receding jet is generally rather weak. In radio bands, it usually peaks at a time of $t\ge 1000$ d, with the peak flux nearly 4 orders of magnitude lower than the peak flux of the forward jet. Also, it usually manifests as a short plateau in the total afterglow light curve, but not as an obvious rebrightening as once expected. In optical bands, the contribution from the receding jet is even weaker, with the peak flux being $\sim 8$ orders of magnitude lower than the peak flux of the forward jet. We thus argue that the emission from the receding jet is very difficult to detect. However, in some special cases, i.e., when the circum-burst medium density is very high, or if the parameters of the receding jet is quite different from those of the forward jet, the emission from the receding jet can be significantly enhanced and may still emerge as a marked rebrightening. We suggest that the search for receding jet emission should mostly concentrate on nearby gamma-ray bursts, and the observation campaign should last for at least several hundred days for each event.

A few citations added, together with a few minor revisions, main conclusions unchanged, accepted for publication in A&A, 7 figures, 10 Pages

References in corpus (7)

• Gamma-Ray Bursts
• A Cosmology Calculator for the World Wide Web
• A Comprehensive Analysis of Swift/XRT Data: III. Jet Break Candidates in X-ray and Optical Afterglow Lightcurves
• The Dynamics and Afterglow Radiation of Gamma-Ray Bursts. I. Constant Density Medium
• Detailed study of the GRB 030329 radio afterglow deep into the non-relativistic phase
• Polarization in the prompt emission of gamma-ray bursts and their afterglows
• A two component jet model for the X-ray afterglow flat segment in short GRB 051221A

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• Detecting Radio Afterglows of Gamma-Ray Bursts with FAST
• Late-Time Afterglow from Double-Sided Structured Jets: Application to GRB 170817A
• Multi-Peaked Non-Thermal Light Curves from Magnetar-Powered Gamma-Ray Bursts
• Prompt emission from the counter jet of a short gamma-ray burst
• The Detection Prospect of the Counter Jet Radiation in the Late Afterglow of GRB 170817A