Cosmic-Ray Sources  

In General
* Primary source: 1990, Not yet exactly known; Probably multiple origin, with lower-energy (< 1015 eV) electrons and ions accelerated by supernova shocks in our galaxy, and more energetic ones extragalactic; 1995, First evidence of cosmic rays from supernova [@ Koyama et al Nat(95)nov]; 2007, High-energy cosmic rays originate in AGNs (probably accelerated by a stochastic process of multiple bounces off moving clouds carrying magnetic fields); 2009, Gamma-ray emission from ordinary galaxies supports idea that lower-energy cosmic rays originate mostly from shock waves in supernova remnants, although some argue that the link is actually to star-forming regions rather than SNRs; 2013, Supernova origin of galactic cosmic rays confirmed.
@ General references: Dar & De Rújula PRP(08)hp/06 [single type of extrasolar source]; Abraham et PA a0907-conf; Drury APP(12)-a1203; Istomin a1406 [extragalactic and galactic]; Drury a1412-conf.
@ Galactic center: Guo et al NJP(13)-a1101-ln; Istomin NA(14)-a1110; Abramowski et HESS Nat(16)mar-a1603 [PeV protons]; Fujita et al a1603 [Sgr A*].
@ Other galactic sources: Butt Nat(09)aug-a1009; Prantzos A&A(12)-a1112; Blasi NPPS(13)-a1211; news pw(13)feb; Amato IJMPA(14).
@ Extragalactic sources: Kashiyama & Mészáros ApJL(14)-a1405 [galaxy mergers]; Settimo a1612-proc [rev].
@ Supernovae: Dar NCB(04)ap/04 [bipolar jets]; Berezhko & Voelk ApJL(07)-a0704 [remnants]; Tatischeff PoS-a0804; Cardillo et al NPPS(14)-a1410; Morlino a1611-ch, a1706-IAU [rev].
@ Galactic vs extragalactic: Allard et al APP(07)ap/05; Aloisio et al PRD(08); Berezinsky APP(14)-a1301-conf [signatures].
@ Other types of sources: Vachaspati PRD(10) [from cusps on cosmic strings].
@ Anisotropy: Mollerach a0902-proc; Toscano et IceCube a1011, news livesci(10)aug [evidence from IceCube]; Giacinti et al JCAP(12)-a1112 [and transition from galactic to extragalactic cosmic rays]; Deligny a1612-eConf [rev].

blue bullet Other aspects: see cosmic rays; UHE cosmic rays; propagation [including acceleration mechanisms].

* Spectrum: The observed energy spectrum of cosmic rays on earth is not the source spectrum of these particles.
@ Sources, spectra: Abdo et FLAT PRL(09) + Winstein & Zurek Phy(09) [e+-e spectrum, 20 Gev–1 keV]; Abraham et PA a0907-conf [spectrum]; Schwarzschild PT(10)jan; Halzen a1010-conf; PA Collaboration a1107-conf; > s.a. high-energy cosmic rays [acceleration].
@ Spectrum, Tsallis statistics: Beck PhyA(04); Włodarczyk & Wilk a0706-conf [thermal sources].
@ Spectrum features: Apel et KASKADE-Grande Collaboration PRL(11) [second knee-like structure]; Giacinti et al PRD(14)-a1403 [the knee and cosmic-ray escape from the galaxy]; Deligny CRP(14)-a1403 [interpretation of the ankle]; Giacinti et al PRD(14) [spectrum above the knee as escape from the galaxy]; Widom et al a1501 [the knee as sign of a second-order phase transition].

Ultra-High-Energy Cosmic Rays > s.a. GZK Effect.
* Idea: The most likely candidates are supernovae, gamma-ray bursts (GRBs) and active galactic nuclei (AGNs).
@ General references: Farrar ap/05 [5-event cluster]; Pierpaoli & Farrar ap/05 [galaxy clusters]; Jain & Panda ap/05 [not primordial black holes]; Erlykin & Wolfendale JPG(05)ap; Blasi MPLA(05)ap; Inoue ap/07-conf; Fraschetti PTRS(08)-a0809 [rev, and propagation]; Waxman & Loeb JCAP(09)-a0809 [transient sources]; Katz et al JCAP(09) [flux and spectrum]; Farrar et al a0904, a0904 [correlations]; Albuquerque & Chou JCAP(10)-a1001 [highest-energy Auger event]; Aloisio & Boncioli APP(11)-a1002 [model for effects of source distribution]; Piran a1005 [composition and distances]; Stanev MPLA(10) [review]; Dado et al NCC-a1011; Vladimirov et al ApJ(12)-a1108; Pe'er & Loeb JCAP(12)-a1111 [constraints from high-energy Fermi satellite observations]; Yoshida & Ishihara PRD(12) [and neutrinos]; Aloisio EPJwc(13)-a1207 [galactic and extra-galactic]; Blasi CRP(14)-a1403; Anchordoqui a1707-proc; Fargion PoS-a1805.
@ AGNs: Auger Collaboration Sci(07)-a0711 + pw(07)nov + PT(08)jan [nearby]; Gorbunov et al a0804; Moskalenko et al ApJ(09)-a0805, Stanev a0805 [criticism]; Nagar & Matulich A&A(08)-a0806 [Auger, nearby radio galaxies]; Hardcastle et al MNRAS(09)-a0808 [Centaurus A]; Biermann et al IJMPD(09); Fraija et al a1007 [Cen A]; Nemmen et al ApJ(10)-a1007 [Fermi data]; Kim & Kim JCAP(11)-a1009, IJMPD(13)-a1203 [statistical analysis].
@ GRBs: news pw(12)apr [surprisingy few neutrinos from GRBs seen by IceCube]; news ns(12)jul [possible after all]; Mészáros NPPS(14)-a1407 [rev].
> Online resources: see NASA 2017 video.

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