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Astroparticle physics 3. Supernovae, neutrinos and high energy cosmic-rays in the local Universe Alberto Carramiñana Instituto Nacional de Astrofísica, Óptica y Electrónica Tonantzintla, Puebla, México Xalapa, 9 August 2004
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Iben (1967)
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Post main sequence M 8 M Hydrogen burning He core + H burning shell + envelope Helium burning: –Explosive He core burning (previous He flash) CO white dwarf (M < 2.25 M ) –Stable He burning CO core + He burning shell + He layer + H burning shell + envelope (M > 2.25 M )
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Post Main Seq. M > 8 M Nuclear processes: –He burning (10 8 K) together with –neutrino cooling (dominant from 5 10 8 K) –carbon burning (6 10 8 K) –oxygen burning (10 9 K) CO flash ignition SN (I½ probably! and Ia by accretion) for not so massive stars
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The path to the Iron catastrophe Above 8 M : onion structure degenerate iron core Succesive reactions (Si, S, Ar,...) : less energy per nucleon. Enhanced emission: Photodisintegration Electron capture: Arnett, Bahcall, Kirschner & Woosley (1989)
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Core collapse For an isothermal star supported by a non relativistic degenerated gas: –electron degeneracy – neutron degeneracy Electron absorption loss of e-degeneracy pressure core collapse in free-fall time (v 70,000 km/s) Infall halts at 8 10 14 g cm –3 nucleus rebound.
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Supernova explosion Bounce creates an upward prompt shock (stalled by inward shock! ). provide required energy to continue (delayed shock) Initial shock temperature explosive Fe peak nucleosynthesis 0.08-0.40 M of 56 Ni
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SN 1987A
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Feb 23.316, 1987 The brightest in 383 yrs In LMC (D 50 kpc). Intrinsically faint M=-15.5 (“only” 10 9 L ) Blue giant precursor Sk– 69 202, M 16 22 M , core 5 7 M 0.07 M of 56 Ni 56 Co
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Neutrinos from SN1987A First observational evidence of neutron star formation Observed by at least two experiments. Neutrinos from bounce (1% in 20 ms) and from cooling (99% in few s) Arnett, Bahcall, Kirschner & Woosley (1989)
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Neutrino properties from SN1987A Neutrino mass 16 eV Neutrino charge Lifetime Same speed and geodesics for neutrinos and photons (within 10 -8 )
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The local group of Galaxies
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Cosmic-ray all energy spectrum Power-law: Secondaries (B) have steeper spectra than primaries (C,O). k = 2.7 k = 3.0 k = 2.8 15/27
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Cosmic-rays: propagation Cosmic-rays do not propagate in straight lines: trapped by Galactic magnetic field (average 3 G) Transport equation: –Leaky box model: CR travel path: Proton injection spectrum: – 10 Be (mean life 3.9 Myrs) analysis: (Garcia-Muñoz, Mason & Simpson 1977)
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Cosmic-rays below the knee Knee: 10 15 eV when: –a h(disc) –Theoretical sources loose efficiency Directional information?
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Cosmic-ray sources: limits Few sources with enough energetics Waxman, astro-ph/0310079
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GZK limit Greisen-Zatsepin –Kuzmin (1966)
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Or no GZK limit? 20/27
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The local Universe Normal and radio galaxies.
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Nearby cosmic rays? Galactic halo? Concentrations of galaxies in the nearby Universe (red) and voids (yellow); if the cosmic rays were coming from radio galaxies or quasars we would expect some bias towards these directions. Hillas (1998) 4% anisotropy above 1e18 eV (AGASA experiment)
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Extragalactic -ray sources Blazars (“radio loud flat spectrum AGNs”) Typically at high redshifts (z 2).
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Active Galaxies AGN zoo: –Starburst –Seyferts & radio galaxies –Quasars, BL Lacs AGN standard model: –accreting supermassive black hole (10 6 to 10 9 M ) –AGN type depends on orientation
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-ray blazars Over 50 extragalactic EGRET sources: –BL Lacs & FSRQ (z=0.03 to 2.3) Closest: Mk 421 (@120 Mpc), 2230+114 (@ 280 Mpc), –Radiogalaxy Cen A (@ 6 Mpc) –Spectra cannot show 0 bumps (GLAST?) Synchrotron Self-Compton models: hadronic & leptonic 25/27
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TeV detections Mk 421: the nearest EGRET FSRQ (@120 Mpc) Mk 501: nearby FSRQ, undetected by EGRET Both up to 10 TeV GZK-like limit? FIR background...
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The GZK problem High energy cosmic-rays must be extragalactic. High energy cosmic-rays must come from nearby (less than 50 Mpc). No obvious sources within GZK distance –unless all HECRs come from Cen A (and simils...) –unclear anisotropy / point source situation... Top-down scenario? The Pierre Auger Observatory
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