Speaker
Description
We investigate the effect of photon-axion-like particle (ALP) oscillations in the gamma-ray spectra of FSRQ B1426+326 measured by Fermi-LAT and MAGIC around the flaring activity in January 2020. We set 95% confidence level (C.L.) upper limit on the photon-ALP coupling constant $g_{a\gamma} < 2\times10^{-11}$ GeV$^{-1}$ for ALP masses $m_{a} \sim 10^{-10}-10^{-9}$ eV. Assuming the hadronic origin of very-high-energy (VHE) photons, we also estimate the expected neutrino flux and the cumulative flux from QSO B1420+326-like FSRQs at sub-PeV energies. Furthermore, we study the implications of photon-ALP oscillations on the counterpart $\gamma$-rays of the sub-PeV neutrinos. Finally, we investigate a viable scenario of invisible neutrino decay to ALPs on the gamma-ray spectra and diffuse $\gamma$-ray flux at sub-PeV energies. Interestingly, we find that for the choice of neutrino lifetime $\tau_{2}/m_{2} = 10^3$ s eV$^{-1}$, the $\gamma$-ray flux has a good observational sensitivity towards LHAASO-KM2A.
| Reference publication/preprint | arXiv:2310.16634 |
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| Designation | Student |
| Institution | Indian Institute of Technology Jodhpur |
