Implications of a proton blazar inspired model on correlated observations of neutrinos with gamma-ray flaring blazars

Abstract

Recent detection of the neutrino events IceCube-170922A, 13 muon-neutrino events observed in 2014-2015 and IceCube-141209A by IceCube observatory from the Blazars, namely TXS 0506+056, PKS 0502+049/TXS 0506+056 and GB6 J1040+0617 respectively in the state of enhanced gammaray emission, indicates the acceleration of cosmic rays in the blazar jets. The photo-meson (pγ) interaction cannot explain the IceCube observations of 13 neutrino events. The non-detection of broadline emission in the optical spectra of the IceCube blazars, however, question the hadronuclear (pp) interaction interpretation through relativistic jet meets with high density cloud. In this work, we investigate the proton blazar model in which the non-relativistic protons that come into existence under the charge neutrality condition of the blazar jet can offer sufficient target matter for pp interaction with shock-accelerated protons, to describe the observed high-energy gamma-rays and neutrino signal from the said blazars. Our findings suggest that the model can explain consistently the observed electromagnetic spectrum in combination with appropriate number of neutrino events from the corresponding blazars.PACS numbers: 96.50.S-, 98.70.Rz, 98.70.Sa

Cosmogenic gamma-ray and neutrino fluxes from blazars associated with IceCube events

“…With observations of several wellreconstructed track events by the new Gold-alert system and the electromagnetic follow-up observations, the detection of neutrino events associated with transient phenomena is now possible. The IceCube events considered here have been studied in the past for self-consistent modeling of the blazar SED and emission of neutrinos from the jets (Banik et al 2020;Petropoulou et al 2020;Rodrigues et al 2021a). In some scenarios, a significant fraction of neutrinos at EeV energies can be attributed to that produced from inside the sources (Rodrigues et al 2021b).…”

Interpreting correlated observations of cosmic rays and gamma-rays from Centaurus A with a proton blazar inspired model

“…A hybrid simulation study which demonstrated that only a small fraction of protons of the system (roughly 4%) are accelerated to non-thermal energies at diffusive shocks, suggests the existence of cold protons in the blazar jets [29]. In principle, cold (non-relativistic) protons that arose from charge neutrality condition, are also assumed to exist in the blazar jets to explain high energy gamma-rays and neutrinos as described in the adopted proton blazar inspired model [27,28]. In the present work we explain the observed high energy gamma-rays and UHECR events from the radio galaxy Cen A based on the proton blazar inspired model [27].…”

“…The synchrotron emission of the electron distribution generally describes the low-energy component of the EM SED of the AGN, which can be numerically estimated following [27,30]. As elaborated in [27,28], the acceleration efficiency of electrons in the AGN jet is likely to be quite low and total number electrons including 'hot' and non-relativistic ('cold') electrons can be determined as ′ = ′ ,ℎ / . In the present work, we have considered the values of ∼ 10 −3 , which is within the permitted range [28,35] and compatible with the hybrid simulation results of diffusive shock acceleration by parallel collision-less shock [36,37].…”

“…As elaborated in [27,28], the acceleration efficiency of electrons in the AGN jet is likely to be quite low and total number electrons including 'hot' and non-relativistic ('cold') electrons can be determined as ′ = ′ ,ℎ / . In the present work, we have considered the values of ∼ 10 −3 , which is within the permitted range [28,35] and compatible with the hybrid simulation results of diffusive shock acceleration by parallel collision-less shock [36,37]. The Fermi−LAT discovery of GeV hardness in the year 2013 and the TeV emission observed during 2004-2008 with H.E.S.S.…”

“…In the couple of previous works [27,28], we have developed a proton blazar inspired model which can describe consistently the observed high energy gamma rays and neutrino signal from all the three Icecube blazars (i.e, TXS 0506+056, PKS 0502+049, GB6 J1040+0617) [27,28] assuming that the association of the observed neutrino events with the corresponding blazars at the flaring stage are genuine. Basically the model explains the high energy gamma-ray and neutrino observations based on interactions of shock accelerated protons in AGN jet with the cold protons present in the system.…”