Year: 2026
Type: article
Abstract: The 1–100-pc region embedding long-duration gamma-ray bursts (GRBs) has been hitherto unexplored, as extremely high ionization by the GRB prevents the application of optical absorption spectroscopy at such distances. Here we show that the ionizing flux of the GRB imprints a unique time- and spatially dependent ionization structure on the gas, which can be probed by X-ray absorption. Application of this model to a selected sample of seven bright GRB X-ray afterglow spectra observed by XMM-Newton EPIC-pn enables an independent, quantitative estimation of the density (log( n ) ≈ 2–4) and distances (5–100 pc) of the ionized absorber directly from the GRB X-ray spectrum, thereby allowing us to locate the absorbing medium of this representative sample of long-duration GRBs in the region of the density–size diagram populated by star-forming regions versus other gravitationally bound objects in the Universe. Our results provide one of the most direct links between long-duration GRBs and star formation and show the potential of high-resolution X-ray spectroscopy as a powerful probe of star-forming regions that embed GRBs up to the highest redshifts.
Source: Nature Astronomy
Institutions: Institute for Space Astrophysics and Planetology, Astronomical Observatory of Rome, National Institute for Astrophysics, Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Osservatorio di Astrofisica e Scienza dello Spazio, University of Calabria, Universidad Nacional Autónoma de México, University of the Virgin Islands, The University of Western Australia
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $12,690
OpenAlex ID: W7128993054