A. Śmiałkowski | Searcharxiv

arXiv2022

Contribution to the extragalactic neutrino background from dense environment of GRB jets

Long gamma-ray bursts (GRBs) are at present well confirmed sites of acceleration of particles to relativistic energies due to observations of gamma-ray emission in the GeV-TeV energy range. We consider a scenario in which the mechanism accelerating electrons is also responsible for acceleration of hadrons in the GRB jets to multi-PeV energies. Since progenitors of long GRBs are massive stars still immersed in dense stellar clusters, these hadrons can efficiently interact with the matter after escaping from the jet. We calculate the spectra of neutrinos from the interaction of those hadrons with the matter of a huge cloud surrounding GRB. Those neutrinos form an afterglow on a time scale determined by their diffusion time scale in the cloud. Due to this long delay, their identification with any specific GRB is not possible. We estimate contribution of neutrinos from such afterglows to the extragalactic neutrino background recently reported by the IceCube Observatory.

astro-ph.HE↗

arXiv2022

High energy neutrinos from fast winds in Novae

We discuss a scenario in which TeV neutrinos are produced during explosions of Novae. It is argued that hadrons are accelerated to very high energies in the inner part of a Nova wind, as a result of reconnection of the strong magnetic field of a White Dwarf. Hadrons are expected to interact efficiently with a dense matter of the wind, either already during the acceleration process or during their advection with the equatorial wind. We calculate the neutrino spectra, and estimate the muon neutrino event rates in the IceCube telescope, in the case of a few Novae. In general, those event rates are unlikely to be detected with the present neutrino detectors. However, for favourable location of the observer, some neutrino events might be detected not only from the class of Novae recently detected in the GeV $γ$-rays by the {\it Fermi}-LAT telescope but also from novae not detected in $γ$-rays. The GeV $γ$-ray emission observed from Novae cannot originate in terms of the model discussed here, since protons are accelerated within a few stellar radii of the White dwarf, i.e. in the region in which GeV $γ$-rays are expected to be severely absorbed in the interactions with the radiation field and the matter of the wind.

astro-ph.HE↗