Journal article icon

Journal article

Precise measurements of self-absorbed rising reverse shock emission from gamma-ray burst 221009A

Abstract:
Gamma-Ray Bursts (GRBs) are brief flashes of gamma-rays that last from a fraction of second up to a few hundreds of seconds, during which a significant amount of isotropic equivalent energy is released (ranging from 10^48 to 10^54 erg). These explosive transients are associated with the catastrophic explosion of an isolated massive star (long-duration GRBs), or with the merger of compact objects (short-duration GRBs). Both scenarios lead to the formation of a highly magnetised neutron star or a spinning, stellar-mass black hole, which are thought to accrete material and launch two relativistic jets, causing the observed gamma-ray emission via magnetic processes or internal shocks. These jets interact with the surrounding material, producing the afterglow emission that extends from gamma-rays to radio waves. To understand GRB formation and evolution, a standard model involving an ultra-relativistic outflow is commonly employed. However, even sophisticated models face degeneracy in the multi-dimensional parameter space. To alleviate or possibly break the degeneracy, broad-band observations across the electromagnetic spectrum are crucial. In particular, the Very Long Baseline Interferometry technique (VLBI) has proven to be a unique asset, providing direct evidence of apparent superluminal expansion (for on-axis GRBs), centroid displacement of the outflow (for slightly off-axis GRBs) and the first confirmation that merger events can launch successful jets. In this Thesis, we employed radio and VLBI observations to characterise and constrain the outflow, the circum-burst medium, and the properties of the progenitors of GRBs. This included studies on individual events (GRB201015A and GRB221009A), which are important to test the predictions of current models, GRB host galaxies (GRB200716C), which are fundamental to constrain the nature of the progenitor through the characterisation of the surrounding environment, and the statistical properties of GRB afterglows, in order to verify the existence of potential GRB sub-populations
Publication status:
Published
Peer review status:
Peer reviewed

Actions

Access Document

Files:
Publisher copy:
10.1038/s41550-023-01997-9
Publication website:
http://amsdottorato.unibo.it/11467/1/Giarratana_PhD_Thesis.pdf

Authors

More by this author
Institution:
University of Oxford
Role:
Author
ORCID:
0000-0002-7735-5796
More by this author
Institution:
University of Oxford
Role:
Author
ORCID:
0000-0003-2705-4941
More by this author
Role:
Author
ORCID:
0000-0002-0161-7243
More by this author
Institution:
University of Oxford
Role:
Author
ORCID:
0000-0002-5654-2744
More by this author
Role:
Author
ORCID:
0000-0001-9149-6707


Publisher:
Nature Research
Journal:
Nature Astronomy More from this journal
Volume:
7
Issue:
8
Pages:
986-995
Publication date:
2023-06-29
DOI:
EISSN:
2397-3366
ISSN:
2397-3366


Language:
English
Keywords:
Pubs id:
1491415
Local pid:
pubs:1491415
Source identifiers:
W4382722398
Deposit date:
2026-05-11
ARK identifier:
This ORA record was generated from metadata provided by an external service. It has not been edited by the ORA Team.

Terms of use


Views and Downloads






If you are the owner of this record, you can report an update to it here: Report update to this record

TO TOP