Negro, Michela;
Di Lalla, Niccolò;
Omodei, Nicola;
Veres, Péter;
Silvestri, Stefano;
Manfreda, Alberto;
Burns, Eric;
... Xie, Fei; + view all
(2023)
The IXPE View of GRB 221009A.
The Astrophysical Journal Letters
, 946
(1)
, Article L21. 10.3847/2041-8213/acba17.
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Abstract
We present the IXPE observation of GRB 221009A, which includes upper limits on the linear polarization degree of both prompt and afterglow emission in the soft X-ray energy band. GRB 221009A is an exceptionally bright gamma-ray burst (GRB) that reached Earth on 2022 October 9 after traveling through the dust of the Milky Way. The Imaging X-ray Polarimetry Explorer (IXPE) pointed at GRB 221009A on October 11 to observe, for the first time, the 2–8 keV X-ray polarization of a GRB afterglow. We set an upper limit to the polarization degree of the afterglow emission of 13.8% at a 99% confidence level. This result provides constraints on the jet opening angle and the viewing angle of the GRB, or alternatively, other properties of the emission region. Additionally, IXPE captured halo-rings of dust-scattered photons that are echoes of the GRB prompt emission. The 99% confidence level upper limit to the prompt polarization degree depends on the background model assumption, and it ranges between ∼55% and ∼82%. This single IXPE pointing provides both the first assessment of X-ray polarization of a GRB afterglow and the first GRB study with polarization observations of both the prompt and afterglow phases.
Type: | Article |
---|---|
Title: | The IXPE View of GRB 221009A |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.3847/2041-8213/acba17 |
Publisher version: | https://doi.org/10.3847/2041-8213/acba17 |
Language: | English |
Additional information: | Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence (http://creativecommons.org/licenses/by/4.0/). Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. |
Keywords: | Gamma-ray bursts; Polarimetry; X-ray astronomy |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
URI: | https://discovery.ucl.ac.uk/id/eprint/10167801 |
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