On the Neutrino Flares from the Direction of TXS 0506+056

Abstract

For the first time since the discovery of high-energy cosmic neutrinos by IceCube, a multimessenger campaign identified a distant gamma ray blazar, TXS 0506+056, as the source of a high-energy neutrino. The extraordinary brightness of the blazar despite its distance suggests that it may belong to a special class of sources that produce cosmic rays. Moreover, over the last 10 years of data, the high-energy neutrino flux from the source is dominated by a previous neutrino flare in 2014, which implies that flaring sources strongly contribute to the cosmic ray flux. We investigate the contribution of this subclass of flaring blazars to the high-energy neutrino flux and examine its connection to the very high energy cosmic ray observations. We also study the high energy gamma ray emission accompanying the neutrino flare and show that the sources must be more efficient neutrino than gamma ray emitters. This conclusion is supported by the gamma-ray observations during the 2014 neutrino flare.

Compact Bright Radio-loud AGNs. III. A Large VLBA Survey at 43 GHz

“…Recently, the source of high-energy cosmic neutrinos (∼300 TeV) detected by IceCube on 2017 September 22 was identified as a distant γ-ray blazar, TXS 0506+056, which is an intermediate synchrotron-peaked BL Lac object at a redshift of z = 0.34 (Halzen et al 2019;IceCube Collaboration et al 2018a,b). This first confirmed that blazars are sources of high-energy astrophysical-origin neutrinos, opening a new window of studying the Universe using the unobstructed messenger neutrino (IceCube Collaboration et al 2018b).…”

Detection of a flaring blazar coincident with an IceCube high-energy neutrino

“…This finding triggered a search for lower-energy (O(10 TeV)) archival neutrinos from the position of TXS 0506+056 , which revealed an excess of neutrinos in a time window of 158 days between September 2014 and March 2015 with a 3.5σ significance [16] (more details in Finley et al in these proceedings) without a coincident gamma-ray flare. Simple models so far cannot explain both IceCube-170922A and the 2014/15 neutrino flare in one consistent picture [17][18][19]. Detailed analyses of archival IceCube and Fermi data combined with more detections of high-energy neutrinos connected to blazars in the future might shed more light on particle acceleration in blazar jets.…”

Multimessenger Search for the Sources of Cosmic Rays Using Cosmic Neutrinos

“…where ξ z is a factor of order unity that parameterizes the integration over the redshift evolution of the sources (Halzen et al, 2018). Applying this relation to the 2014 TXS 0506+056 burst that dominates the flux over the 9.5 years of neutrino observations, yields…”