Observability of the very-high-energy emission from GRB 221009A

The LHAASO Collaboration detected the gamma ray burst GRB 221009A at energies above $500 \, {\rm GeV}$ with a tail extending up to $18 \, \rm TeV$, whose spectral analysis has presently been performed up to $7 \, \rm TeV$ for the lower energy instrument LHAASO-WCDA only, with no indication of a cutoff. Soon thereafter, Carpet-2 at Baksan Neutrino Observatory reported the observation of an air shower consistent with being caused by a photon of energy $251 \, {\rm TeV}$ from the same GRB. Given the source redshift $z=0.151$, the expected attenuation due to the extragalactic background light is very severe so that these detections have proven very hard to explain. In this Letter, we show that the existence of axion-like-particles (ALPs) with mass $m_a \simeq (10^{-11}-10^{-7}) \, {\rm eV}$ and two-photon coupling $g_{a \gamma \gamma} \simeq (3-5) \times 10^{-12} \, {\rm GeV}^{- 1}$ strongly reduce the optical depth of TeV photons, thus explaining the observations. Our ALPs meet all available constraints, are consistent with two previous hints at their existence and are good candidates for cold dark matter. Moreover, we show that Lorentz Invariance Violation (LIV) can explain the Carpet-2 result but not the LHAASO observations.

Volume

131

Issue

25

Uri

http://hdl.handle.net/20.500.12386/37039

Url

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.251001

http://arxiv.org/abs/2210.05659v8

Issn Identifier

0031-9007

Rights

open.access

File(s)

Name

2210.05659v8-compressed.pdf

Description

Postprint

Size

9.95 MB

Format

Adobe PDF

Checksum (MD5)

4426c22da3e8a087882a94f81d489b2b

Name

PhysRevLett.131.251001.pdf

Description

[Administrators only]

Size

632.35 KB

Format

Adobe PDF

Checksum (MD5)

4ebd79ba3f16b9dbd909947a48fae55e

Observability of the very-high-energy emission from GRB 221009A

Explore By

Information and guides for authors