The Power of the Rings: The GRB 221009A Soft X-Ray Emission from Its Dust-scattering Halo

Tiengo, Andrea; Pintore, Fabio; Vaia, Beatrice; Filippi, Simone; Sacchi, Andrea; Esposito, Paolo; Rigoselli, Michela; Mereghetti, Sandro; Salvaterra, Ruben; Šiljeg, Barbara; Bracco, Andrea; Bošnjak, Željka; Jelić, Vibor; Campana, Sergio (2023) The Power of the Rings: The GRB 221009A Soft X-Ray Emission from Its Dust-scattering Halo. The Astrophysical Journal Letters, 946 (1). ISSN 2041-8205

PDF - Published Version - article Available under License Creative Commons Attribution. Download (3MB)

Abstract

GRB 221009A is the brightest gamma-ray burst (GRB) ever detected that has occurred at low Galactic latitude. Owing to this exceptional combination, its prompt X-ray emission could be detected for weeks in the form of expanding X-ray rings produced by scattering in Galactic dust clouds. We report on the analysis of 20 rings, generated by dust at distances ranging from 0.3 to 18.6 kpc, detected during two X‑ray Multi Mirror (XMM)-Newton observations performed about 2 and 5 days after the GRB. By fitting the spectra of the rings with different models for the dust composition and grain size distribution, we reconstructed the spectrum of the GRB prompt emission in the 0.7-4 keV energy range as an absorbed power law with photon index Γ = 1-1.4 and absorption in the host galaxy N H,z = (4.1-5.3) × 1021 cm-2. Taking into account the systematic uncertainties regarding the column density of dust contained in the clouds producing the rings, the 0.5-5 keV fluence of GRB 221009A can be constrained between 10-3 and 7 × 10-3 erg cm-2. Both the fluence and the photon index indicate the presence of a possible soft excess with respect to the extrapolation of the main GRB peak observed at higher energies.

Item Type:	Article
Uncontrolled Keywords:	Gamma-ray bursts ; Interstellar dust ; Interstellar dust extinction ; Interstellar scattering
Subjects:	NATURAL SCIENCES > Physics > Astronomy and Astrophysics
Divisions:	Division of Experimental Physics
Depositing User:	Vibor Jelić
Date Deposited:	08 Feb 2024 09:26
URI:	http://fulir.irb.hr/id/eprint/8529
DOI:	10.3847/2041-8213/acc1dc

Actions (login required)

View Item