Constraints on the intergalactic magnetic field strength from $\gamma$-ray observations of GRB 221009A

Abstract

Characteristics of the cascade gamma-ray signal resulting from very-high-energy gamma-ray sources, such as gamma-ray bursts, can be used to constrain the strength and structure of intergalactic magnetic fields (IGMF). There has been a debate on whether GRB 190114C, the first gamma-ray burst with observed TeV photons, can constrain the IGMF. Recently, LHAASO detected the brightest-of-all-time GRB 221009A, which has much larger energy in TeV band and the spectrum extends to energy above 10 TeV, providing an unprecedented opportunity to studying IGMF. We perform a Monte-Carlo simulation of the cascade process with the public ELMAG code, considering the TeV data of GRB 221009A observed by LHAASO. By comparing the resulting cascade emission with the flux limit obtained from Fermi-LAT observations, we infer a limit of $B\ge 10^{-18.5}\mathrm{G}$ for IGMF. Though this limit may not be as strong as the limit from blazars, it serves as an independent constraint on IGMF from a new class of TeV sources.

Accepted for publication in ApJ Letters, 9 pages, 3 figures, and 1 table

References in corpus (7)

• Observation of inverse Compton emission from a long $\gamma$-ray burst
• A tera-electronvolt afterglow from a narrow jet in an extremely bright gamma-ray burst 221009A
• Probing the Nature of the Weakest Intergalactic Magnetic Fields with the High Energy Emission of Gamma-Ray Bursts
• GRB 190114C: from prompt to afterglow?
• Synchrotron Radiation Dominates the Extremely Bright GRB 221009A
• Properties of the Intergalactic Magnetic Field Constrained by Gamma-ray Observations of Gamma-Ray Bursts
• Search of the pair echo signatures in the high-energy light curve of GRB190114C

Cited by in corpus (7)

• On the nature of LOFAR RMs and new constraints on magnetic fields in cosmic filaments and on magnetogenesis scenarios
• Prospects for detection of the pair-echo emission from TeV gamma-ray bursts
• Constraints on the intergalactic magnetic field from Fermi-LAT observations of GRB 221009A
• New Insights on Gamma-Ray Burst Radiation Mechanisms from Multiwavelength Observations
• Intergalactic magnetic field lower limits up to the redshift $z\approx 3$
• X-ray polarimetric features of Gamma-ray Bursts across varied redshifts and hints for Axion-Like-Particles
• Modeling the imprints of large-scale magnetized structures on $\gamma$-rays from extragalactic transients