1

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

4

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).

6

Preliminary

Contribution from Extragalactic pulsar population

Upper limit of rotational speed

< 0.01%

galaxy density = 0.02 Mpc-3

7

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

8

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