Neutrino Counterparts of Fast Radio Bursts

Abstract

The discovery of a luminous radio burst, FRB 200428, with properties similar to those of fast radio bursts (FRB), in coincidence with an X-ray flare from the Galactic magnetar SGR 1935+2154, supports magnetar models for cosmological FRBs. The burst's X-ray to radio fluence ratio, as well as the X-ray spectral shape and peak energy, are consistent with FRB 200428 being the result of an ultra-relativistic shock (powered, e.g., by an ejected plasmoid) propagating into a magnetized baryonrich external medium; the shock simultaneously generates X-ray/gamma-rays via thermal synchrotron emission from electrons heated behind the shock, and coherent radio emission via the synchrotron maser mechanism. Here, we point out that a unique consequence of this baryon-loaded shock scenario is the generation of a coincident burst of high-energy neutrinos, generated by photo-hadronic interaction of relativistic ions−heated or accelerated at the shock−with thermal synchrotron photons. We estimate the properties of these neutrino burst FRB counterparts and find that a fraction ∼ 10 −8 − 10 −5 of the flare energy (or ∼ 10 −4 − 10 −1 of the radio isotropic energy) is channeled into production of neutrinos with typical energies ∼ TeV−PeV. We conclude by discussing prospects for detecting this signal with IceCube and future high-energy neutrino detectors.

Using High-Energy Neutrinos As Cosmic Magnetometers

“…Fast radio bursts (FRBs) have been considered as potential neutrino sources, but their feasibility as such depends on their origin, which is currently subject of intense investigation. So far, direct searches have found no evidence for FRBs as high-energy neutrino sources [97][98][99][100][101]. If FRBs are connected to magnetars [102][103][104][105][106][107], then our limits would disfavor relativistic outflows in FRBs as regions of copious production of high-energy neutrinos.…”

Search for low-energy signals from fast radio bursts with the Borexino detector

“…Background components contained in the bulk can be reduced by applying a cut on the visible energy. This is important specifically due to the presence of 14 C in the scintillator. The carbon isotope 14 C produces a β-spectrum with an endpoint of 156 keV and has an activity of roughly 110 Bq in the whole inner vessel.…”

“…This is important specifically due to the presence of 14 C in the scintillator. The carbon isotope 14 C produces a β-spectrum with an endpoint of 156 keV and has an activity of roughly 110 Bq in the whole inner vessel. The presence of this spectral component sets the lower threshold of the analysis at 250 keV of the visible energy.…”

“…In our case the fiducial volume is defined such that all events within 75 cm to the IV are discarded, which corresponds to 3 standard deviations of position reconstruction uncertainty at the lowest energy threshold. The corresponding fiducial volume has a mass of 145 t. The Borexino dataset from May 15, 2007, (corresponding to the detector operation start) to June 21, 2021, was used for the temporal correlation 2 The visible energy spectrum of 14 C is broadened up to this value due to the detector energy resolution and its pile-up.…”

“…Single-burst FRB models involve processes of supernova evolution, mergers, and collapses of neutron stars [10][11][12][13] with emission of neutrinos [14][15][16][17] (and possibly axions) which could be potentially detected by large-volume Cherenkov or scintillation detectors. The IceCube Neutrino Observatory has searched for spatial and temporal correlation between events with energies above 50 GeV, as well as temporal correlation between MeV events and 28 FRBs.…”