newly born pulsars as sources of high and ultrahigh energy cosmic rays
DESCRIPTION
Newly Born Pulsars as Sources of High and Ultrahigh Energy Cosmic Rays. Ke Fang University of Chicago ISCRA - Jul 9, 2012. KF, Kotera , Olinto 2012, ApJ , 750, 118 KF, Kotera , Olinto 2012, in prep. UHECR Observational Facts. GRB AGN Clusters Pulsars. ✓✓ ✓✓. ✗✗✗✓. - PowerPoint PPT PresentationTRANSCRIPT
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Newly Born Pulsars as Sources of High and
Ultrahigh Energy Cosmic RaysKe Fang
University of ChicagoISCRA - Jul 9, 2012
KF, Kotera, Olinto 2012, ApJ, 750, 118 KF, Kotera, Olinto 2012, in prep
GRB AGN Clusters Pulsars
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UHECR Observational FactsEnergy Spectrum
Chemical Composition
TA favors light
composition
Pedro Facal San Luis, ICRC 2011 2
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Abbasi et al. 2009Abraham et al. 2010bKotera & Olinto 2011
Fe-peaked elements strippedoff star surface by E-field
I Newly Born PulsarsHeavy nuclei abundant Fast rotational speedStrong magnetic field
Ruderman & Sutherland 75, Arons & Scharlemann 79, Blasi et. al 00,Arons 03, Bednarek & Bartosik 04, K.F., Kotera, Olinto 12
cosmic ray charge
wind acc. efficiency = 10%
Injection index too hard!
P ~ 0.6 ms
3
B ~ 1012 G
toy model
const velocity
column density
ejecta energy ejecta mass
Unipolar induction
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Pulsars that allow escapeEej=1052 ergsMej=10 Msun
η=0.1
UHE Protons can hardly escape (except for very dilute envelope)
UHE Irons can be accelerated and escape fromms pulsar Ω ~ 104 s-1 with B ~ 1012 – 1013 G
Two competing timescales:Time to escape
CR Life time
To successfully escape:
Our successful UHECR source: ms pulsar in core-collapse supernova
Upper limit of rotational speed
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Simulation of Injected and Escaped Spectrum
Proton Iron
Pure Protons above 10 EeV cannot escape!
~E-2
Injected
escapedlight heavy
Monte-Carlo propagation, hadronic interactions with EPOS + CONEX
Injected
escaped primary
escaped secondary
dN/d log B
11.55 12.65 13.75 log B [G]
dN/d P
150 300 450 600 P [ms]
Faucher-Giguere & Kaspi 06
Pulsar distribution in the galaxy
Conclusion I: ≲ 0.01% of extragalactic pulsar (normal pulsar birth rate 10-4 Mpc-3 yr-
1) can reproduce measured UHECR flux, spectrum and composition (by Auger).
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Preliminary
Contribution from Extragalactic pulsar population
Upper limit of rotational speed
< 0.01%
galaxy density = 0.02 Mpc-3
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Has to be another source!
Extragalactic sourcesGalactic sources
dN/d log B
11.55 12.65 13.75log B [G]
dN/d P
150 300 450 600 P [ms]
Faucher-Giguere & Kaspi 06 Galactic Pulsar?
Upper limit of rotational speed
SNR EG Pulsar AGN Clusters
Spectrum & Composition above the knee
GRB
SNR, Fe tail Emax= 1016-17 eV
Intermediate, not Fe/P!
EG, Proton
Gal Pulsar
SNR, Fe tail Emax= 1016-17 eV
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KF, Kotera, Olinto in prep
Contribution from Galactic and Extragalactic pulsar population
Conclusion II: Galactic and Extragalactic pulsars can be the dominant source above ~1016 eV !
Fit with Auger data3%Fe+22%CNO+40%He+35%P
Fit with TA data23%Fe+22%CNO+40%He+15%P
Halo Height
B-field coherence length