We consider a mechanism that causes a decrease in the attenuation of high energy gamma-ray flux from gamma ray burst GRB 221009A. The mechanism is based on the existence of a heavy m_{N}∼(0.1-1) MeV mostly sterile neutrino N which mixes with active neutrinos. N's are produced in the gamma-ray burst (GRB) in π and K decays via mixing with ν_{μ}. They undergo the radiative decay N→νγ on the way to Earth. The usual exponential attenuation of gamma rays is lifted to an attenuation inverse in the optical depth. Various restrictions on this scenario are discussed. We find that the high energy γ events at 18 TeV can be explained if (i) the GRB active neutrino fluence is close to the observed limit, (ii) the branching ratio of N→νγ is at least of the order 10%.
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http://dx.doi.org/10.1103/PhysRevLett.131.021002 | DOI Listing |
Phys Rev Lett
August 2024
Key Laboratory of Particle Astrophysics and Experimental Physics Division and Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China.
Science
July 2024
Osservatorio Astronomico di Brera, Istituto Nazionale di Astrofisica, Merate 23807, Italy.
A long gamma-ray burst (GRB) is observed when the collapse of a massive star produces an ultrarelativistic outflow pointed toward Earth. Gamma-ray spectra of long GRBs are smooth, typically modeled by joint power-law segments describing a continuum, with no detected spectral lines. We report a significant (>6σ) narrow emission feature at ~10 mega-electron volts (MeV) in the spectrum of the bright GRB 221009A.
View Article and Find Full Text PDFIdentifying the sites of r-process nucleosynthesis, a primary mechanism of heavy element production, is a key goal of astrophysics. The discovery of the brightest gamma-ray burst (GRB) to date, GRB 221009A, presented an opportunity to spectroscopically test the idea that r-process elements are produced following the collapse of rapidly rotating massive stars. Here we present James Webb Space Telescope observations of GRB 221009A obtained +168 and +170 rest-frame days after the gamma-ray trigger, and demonstrate that they are well described by a SN 1998bw-like supernova (SN) and power-law afterglow, with no evidence for a component from r-process emission.
View Article and Find Full Text PDFNat Commun
May 2024
Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, 210023, China.
Large High Altitude Air Shower Observatory has detected 0.2 - 13 TeV emission of GRB 221009A within 2000 s since the trigger. Here we report the detection of a 400 GeV photon, without accompanying prominent low-energy emission, by Fermi Large Area Telescope in this direction with a 0.
View Article and Find Full Text PDFPhys Rev Lett
December 2023
INAF, Osservatorio Astronomico di Brera, Via Emilio Bianchi 46, I-23807 Merate, Italy.
The LHAASO Collaboration detected the gamma ray burst GRB 221009A at energies above 500 GeV with a tail extending up to 18 TeV, whose spectral analysis has presently been performed up to 7 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 TeV from the same GRB. Given the source redshift z=0.
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