A Time-Variability Test for Candidate Neutrino Sources Observed with IceCube

Abstract:

IceCube is a cubic-kilometer neutrino detector deployed deep in the ice at the geographic South Pole [1]. Reconstruction of the direction, energy and flavor of the neutrinos relies on the optical detection of Cherenkov radiation produced in the interactions of neutrinos in the surrounding ice or the nearby bedrock. Recent studies [2, 3] have found hints of neutrino emission from blazar TXS 0506+ 056 as well as the Seyfert galaxy NGC 1068. In this era of multimessenger astronomy, IceCube can provide valuable insight into the sources of cosmic rays and high-energy gamma rays as demonstrated by the follow-up of alert IC170922A [4] and its association with the blazar TXS 0506+ 056. Detection of astrophysical neutrinos from known gamma-ray emitters can be the" smoking gun" evidence for a hadronic component in their-ray spectrum. The two objects of interest, a blazar (TXS 0506+ 056) and a nearby Seyfert galaxy (NGC 1068), show differing features in their-ray spectrum. NGC 1068 has shown no signs of-ray variability [5] while≳ TeV neutrinos can be expected from an AGN outflow model [6]. Additionally, more than 50% of the bright AGN Fermi LAT sample (LBAS) was found to be variable with a high significance [7]. More interestingly,-ray variability in LBAS blazars can be perturbations in mostly steady emission or a series of possibly overlapping flares, which can be understood by random walk processes in turbulent flow in the jet or mass accretion avalanches. Neutrino variability, on the other hand, and its correlation with-ray variability is not well understood. For instance, TXS 0506+ 056 shows low-ray variability around the archival IceCube …

Año de publicación:

2021

Keywords:

Fuente:

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