A Wind Environment and Lorentz Factors of Tens Explain Gamma-Ray Bursts X-Ray Plateau

Authors

Hüsne Dereli-Bégué, Bar-Ilan University, Ramat Gan
Asaf Pe’er, Bar-Ilan University, Ramat Gan
Felix Ryde, KTH Royal Institute of Technology and The Oskar Klein Centre
Samantha R. Oates, University of Birmingham
Bing Zhang, University of Nevada, Las Vegas
Maria G. Dainotti, The Graduate University for Advanced Studies

Document Type

Article

Publication Date

9-24-2022

Publication Title

Nature Communications

First page number:

1

Last page number:

10

Abstract

Gamma-ray bursts (GRBs) are known to have the most relativistic jets, with initial Lorentz factors in the order of a few hundreds. Many GRBs display an early X-ray light-curve plateau, which was not theoretically expected and therefore puzzled the community for many years. Here, we show that this observed signal is naturally obtained within the classical GRB fireball model, provided that the initial Lorentz factor is rather a few tens, and the expansion occurs into a medium-low density wind. The range of Lorentz factors in GRB jets is thus much wider than previously thought and bridges an observational gap between mildly relativistic jets inferred in active galactic nuclei, to highly relativistic jets deduced in few extreme GRBs. Furthermore, long GRB progenitors are either not Wolf-Rayet stars, or the wind properties during the final stellar evolution phase are different than at earlier times. Our model has predictions that can be tested to verify or reject it in the future, such as lack of GeV emission, lack of strong thermal component and long (few seconds) variability during the prompt phase characterizing plateau bursts.

Controlled Subject

Physical sciences; Gamma radiation; Roentgen rays

Disciplines

Other Astrophysics and Astronomy | Physical Processes

File Format

PDF

File Size

1000 KB

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Repository Citation

Dereli-Bégué, H., Pe’er, A., Ryde, F., Oates, S. R., Zhang, B., Dainotti, M. G. (2022). A Wind Environment and Lorentz Factors of Tens Explain Gamma-Ray Bursts X-Ray Plateau. Nature Communications 1-10.
http://dx.doi.org/10.1038/s41467-022-32881-1