Describing correlated observations of neutrinos and gamma-ray flares from the blazar TXS 0506+056 with a proton blazar model

Abstract

Recent detection of the neutrino event, IceCube-170922A by IceCube observatory from the Blazar TXS 0506+056 in the state of enhanced gamma ray emission indicates for acceleration of cosmic rays in the blazar jet. The non-detection of the broadline emission in the optical spectrum of TXS 0506+056 and other BL Lac objects suggests that external photons emissions are weak and hence photo-meson (pγ) interaction may not be a favored mechanism for high energy neutrino production. The lack of broadline signatures also creates doubt about the presence of a high density cloud in the vicinity of the super-massive black hole (SMBH) of TXS 0506+056 and consequently raised question on hadronuclear (pp) interaction interpretation like relativistic jet meets with high density cloud. Here we demonstrate that non-relativistic protons in the proton blazar model, those come into existence under charge neutrality condition of the blazar jet, offer sufficient target matter for pp−interaction with shock accelerated protons and consequently the model can describe consistently the observed high energy gamma rays and neutrino signal from the blazar TXS 0506+056.PACS numbers: 96.50.S-, 98.70.Rz, 98.70.Sa

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

“…In a previous work it was demonstrated that a proton Blazar model can describe consistently the observed high energy gamma rays and neutrino signal from the blazar TXS 0506+056 [21]. In the present work we would like to demonstrate that the proton blazar model can consistently explain the spectral behavior of observed higherenergy bump of the EM SED along with the observed association of neutrinos from all the three IceCube blazars assuming that the association of the observed neutrino events with the corresponding blazars at the flaring stage are genuine.…”

“…j is the bulk Lorentz factor [28]. In the proton blazar framework, we have assumed a broken power law energy distribution of accelerated relativistic electrons in the blazar jet to explain the lowenergy bump of the SED by synchrotron radiation and can be written as [21,29]…”

“…Due to the inverse Compton (IC) scattering of primary accelerated electrons with the seed photons co-moving with the AGN jet, the emissivity Q c (ǫ ′ c ) of produced gamma-ray photons of energy E ′ c (= m e c 2 ǫ ′ c ) can be obtained as given in [34,35]. The seed photons can be estimated directly from the observed photon flux from the blazar as shown in [21,36] and the IC mechanism can describe lower part of high energy component of EM SED of the blazar.…”

“…We have obtained the stationary state of the population of produced electron distribution N ′ e (γ ′ e ) by using the injection function Q ′ e (γ ′ e ) as a source term in the continuity equation for electrons is given by [38]. After that, the associated stationary synchrotron emission of the produced electrons distribution is evaluated and consequently found again the observable photon spectrum as given in Banik & Bhadra (2019) [21].…”

“…The required accelerated primary proton injection luminosity is estimated to be L ′ p = 10 46 erg/s with the best fit spectral slope of α p = −2.13 and the total kinetic jet power turns out to be 10 48 erg/s. The results for this blazar is discussed in details in [21]. The model fitted parameters are shown in Table I.…”