Significant cocoon emission and photosphere duration stretching in GRB 211211A: a burst from a neutron star - black hole merger

The radiation mechanism (thermal photosphere or magnetic synchrotron) and the progenitor of gamma-ray burst (GRB) are under hot debate. Recently discovered, the prompt long-duration (\(\sim\) 10 s, normally from the collapse of massive stars) property of GRB 211211A strongly conflicts with its assoc...

Full description

Saved in:
Bibliographic Details
Published in:arXiv.org 2023-05
Main Authors: Yan-Zhi, Meng, Xiangyu Ivy Wang, Zi-Ke Liu
Format: Article
Language:English
Subjects:
Afterglows
Black holes
Emission
Gamma ray bursts
Light curve
Massive stars
Neutron stars
Photosphere
Stretching
Synchrotrons
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The radiation mechanism (thermal photosphere or magnetic synchrotron) and the progenitor of gamma-ray burst (GRB) are under hot debate. Recently discovered, the prompt long-duration (\(\sim\) 10 s, normally from the collapse of massive stars) property of GRB 211211A strongly conflicts with its association with a kilonova (normally from the merger of two compact objects, NS-NS, NS-BH, or NS-WD, duration \(\lesssim\) 2 s). In this paper, we find the probability photosphere model with a structured jet can satisfactorily explain this peculiar long duration, through the duration stretching effect (\(\sim\) 3 times) on the intrinsic longer (\(\sim\) 3 s) duration of NS-BH (neutron star and black hole) merger, the observed empirical 2SBPL spectrum (with soft low-energy index \(\alpha\) of \(\sim\) -1) and its evolution. Also, much evidence of the NS-BH merger origin is found, especially the well fit of the afterglow-subtracted optical-NIR light curves by the significant thermal cocoon emission and the sole thermal red kilonova component. Finally, a convincing new explanation for the X-ray afterglow plateau is revealed.
ISSN:2331-8422
DOI:10.48550/arxiv.2304.00893