Particle Acceleration and Gamma-Ray Emission from Blazars Susumu Inoue (MPIK/ICRR) - electron + proton acceleration mechanism - leptonic + hadronic emission components
blazars relativistic jet viewed near-axis mainly electron sync.+ic sync. IC(?) blazar sequence Fossati+ 98 GeV TeV
protons in AGN jets indirect evidence for energetically dominant protons - comparison of radiated vs kinetic energy in blazars Celotti & Ghisellini 00 - absence of bulk Compton bump vs kinetic power in blazars Sikora & Madejski 00, Sikora+ 09 - comparison of lobe vs ext. ICM pressure in radio galaxies Hardcastle & Worrall 00, Croston+ 08 direct evidence for thermal protons/ions - Faraday depolarization: consistent with external ICM - X-ray spectra: thermal plasma inside(?) lobes Seta, Tashiro, Isobe, SI, in prep., Stawarz+ 12 direct evidence for accelerated protons not conclusive so far
direct evidence for thermal protons/ions in radio lobes? Seta, Tashiro, Isobe, SI, in prep. Suzaku observations of Fornax A evidence for thermal matter inside radio lobes: entrained ambient gas? yellow: lobe thermal orange: lobe nonth. cyan: Galactic halo blue: CXB purple: unresolved pt.
electron acceleration in blazars - SED fitting -> deduce B, γ e,max - Fermi I accel. interpretation τ accel (B,γ e,max ) = τ cool (B,γ e,max ) -> deduce ξ λ/r g for γ e,max object γ e,max ξ FSRQ (3C279) 6x10 3 10 7 HBL (Mrk 421) 4.5x10 5 10 5 SNR/PWN ~10 8-10 9 ~<10 SI, Takahara 96 acceleration time mean free path on magnetic disturbance syn+ic cooling time very inefficient accel. -> very weak B turbulence no accel. of protons to UHE? Mrk 421 3C279 syn. SSC EC syn. SSC
electron acceleration in UHE proton-driven B turbulence c.f. Biermann & Strittmatter 87 consistently interpreted by assuming: turbulence predominantly driven by max energy protons (r g =max. scale) Kolmogorov-like spectrum of turbulence on smaller scales λ(ε)~r g (Ε p,max ) (E/E p,max ) 1/3 log timescale τ [s] 3C 279 Mrk 421 τ accel E 1/3 τ accel E weak turbulence at GeV-TeV: indirect evidence of proton acceleration to UHE? hard proton spectra required 9 12 15 18 log energy E [ev] alternatives? - non-resonant streaming instability? - Fermi II? Lefa+ 11, Tramecere+ 11
proton-induced emission in blazars Mannheim 93 e - +B e - +γ LE p+γ LE N+ π 0, π +- E p,max ~10 17-10 19 ev π 0 2γ π +- µ +- ν e +- +3ν µ +- +B µ +- +γ muon synchrotron γ+γ LE e + e - electron-positron e + e - +B e + e - +γ sync. cascade p+b p+γ proton synchrotron issues in interpretation as dominant emission: 1. low radiative efficiency generally high L kin required 2. poor fit to broadband spectra? 3. t pγ, t pb too long to explain <day timescale X-TeV correlations in HBLs c.f. complicated (non-)correlations in FSRQs Böttcher+ 09 Aharonian 00 Mücke+ 02,03. also p-p π 0 if dense enough Romero+ 3C279
proton synchrotron emission in blazars Aharonian 00
leptonic+hadronic emission model Cerruti, Zech, Boisson, SI, in prep.; also arxiv:1210.5014, 1111.0557 leptonic model of Katarzynski, Sol & Kus 01 - one zone synchrotron+ssc - electron spectrum: phenomenological broken power-law - internal γγ pair production hadronic processes - proton synchrotron - photomeson interactions (SOPHIA) - sync.+ic emission by all secondary pairs - muon synchrotron - Bethe-Heitler pair production - proton index=electron index - maximum proton energy: accel. time vs loss/dynamical time - free parameter: proton/electron ratio EBL: Franceschini+ 08
leptonic emission Cerruti, Zech, Boisson, SI, in prep. PKS 2155-304 e - syn e - SSC
hadronic emission Cerruti, Zech, Boisson, SI, in prep. PKS 2155-304 e - syn p syn π 0 casc. π +- casc. µ syn e - SSC compared to leptonic, high B, small R, high L
leptonic+hadronic emission Cerruti, Zech, Boisson, SI, in prep. PKS 2155-304 e - syn e - SSC π 0 casc. π +- casc. fiducial leptonic parameters vary only proton/electron ratio
leptonic+hadronic emission Cerruti, Zech, Boisson, SI, in prep. PKS 2155-304 e - syn e - SSC π 0 casc. π +- casc. p syn µ syn intermediate B hadronic contribution in multi-tev+mev range distinguishable through variability non-detection -> upper limit on u p /u e
summary - AGN jets likely contain protons - low electron accelerate rate for Fermi I inferred in blazars may be consistent with UHE proton driven turbulence - hadronic emission components potentially mixed with leptonic emission distinguishable through variability