Physical conditions in potential UHECR accelerators Sergey Gureev Astronomy Dept., Moscow State University Ksenia Ptitsyna Physics Dept., Moscow State University Sergey Troitsky Institute for Nuclear Research, Moscow

1.Constraints on astrophysical accelerators:Constraints on astrophysical accelerators: “Hillas plot” radiation losses 2.Particular sites: “Auger” AGNParticular sites: “Auger” AGN manifold of active galaxies an important detail of the Auger correlations correlated objects important experimental updates for specific mechanisms from powerful BL Lacs to low-power Seyferts and LINERS how to calculate the chance probability? CAN THEY ACCELERATE PROTONS TO UHE?

1.Constraints on astrophysical accelerators:Constraints on astrophysical accelerators: “Hillas plot” radiation losses 2.Particular sites: “Auger” AGNParticular sites: “Auger” AGN manifold of active galaxies an important detail of the Auger correlations correlated objects important experimental updates for specific mechanisms from powerful BL Lacs to low-power Seyferts and LINERS how to calculate the chance probability? CAN THEY ACCELERATE PROTONS TO UHE?

Constraints on astrophysical accelerators: “Hillas plot” + radiation losses (electrodynamics) Assumption: particle is accelerated by electromagnetic forces inside an astrophysical accelerator General limitations: geometry radiation losses energetic particles leave the accelerator accelerating charges radiate and loose energy

geometry: the Hillas criterion: Larmor radius < size of accelerator (otherwise lefts the accelerator) E<ZB R maximal energy charge magnetic field size of the accelerator Schluter & Biermann 1950 Hillas 1984 model-independent

Hillas 1984 the (original) Hillas plot

Boratav et al. 2000

radiation losses: rate of E gain < rate of E loss synchrotron curvature

radiation losses: rate of E gain < rate of E loss synchrotroncurvature depend on the mechanism

Limitations due to radiation losses: disagreement on their importance? protons can be accelerated “to (3-5)×10 21 eV … At energies ≥ eV the cosmic ray primaries have to be heavy nuclei” Aharonyan et al “Practically, all known astronomical sources are not able to produce cosmic rays with energies near few times eV” Medvedev 2003

Different acceleration regimes: diffusive (shocks) inductive (one-shot) - synchrotron-dominated losses - curvature-dominated losses

Different acceleration regimes: diffusive (shocks) plot: Medvedev 2003 gets a hit from time to time, radiates synchrotron continuously

Different acceleration regimes: diffusive (shocks) gets a hit from time to time, radiates synchrotron continuously inductive (one-shot) - synchrotron-dominated losses - curvature-dominated losses

Different acceleration regimes: inductive (one-shot) plot: Medvedev 2003 is accelerated and radiates continuously

Different acceleration regimes: diffusive (shocks) gets a hit from time to time, radiates synchrotron continuously inductive (one-shot) is accelerated and radiates continuously - synchrotron-dominated losses - curvature-dominated losses general field configuration

Different acceleration regimes: diffusive (shocks) gets a hit from time to time, radiates synchrotron continuously inductive (one-shot) is accelerated and radiates continuously - synchrotron-dominated losses - curvature-dominated losses general field configuration specific field configuration

Different acceleration regimes: diffusive (shocks) gets a hit from time to time, radiates synchrotron continuously inductive (one-shot) is accelerated and radiates continuously - synchrotron-dominated losses - curvature-dominated losses general field configuration specific field configuration E || B (close to a black hole)

updated Hillas plots (plus radiation constraints) - diffusive acceleration

updated Hillas plots (plus radiation constraints) - inductive acceleration, synchrotron losses

updated Hillas plots (plus radiation constraints) - inductive acceleration, synchrotron losses

updated Hillas plots (plus radiation constraints)

1.Constraints on astrophysical accelerators:Constraints on astrophysical accelerators: “Hillas plot” radiation losses 2.Particular sites: “Auger” AGNParticular sites: “Auger” AGN manifold of active galaxies an important detail of the Auger correlations correlated objects important experimental updates for specific mechanisms from powerful BL Lacs to low-power Seyferts and LINERS how to calculate the chance probability? CAN THEY ACCELERATE PROTONS TO UHE?

Auger correlations with AGN - the “AGN” term is misleading - 20% of galaxies show nuclear activity - luminosity, size, mass scatter by orders of magnitude - powerful BL Lacs and radio galaxies vs. low-power Seyferts and LINERs: quite different positions on the Hillas plot!

Auger correlations with AGN: various AGN on the Hillas plot

Auger correlations with AGN: an important detail how to calculate the chance probability? list of sources list of events calculate number of pairs “source-event” in data compare with expected from Monte-Carlo estimate the chance probability

Auger correlations with AGN: an important detail how to calculate the chance probability? list of sources list of events number of pairs “source-event”: what if there are several sources for one event? 2. “Correlation function”: count every pair 1. “Nearest neighbour”: one source for one event

Auger correlations with AGN: an important detail how to calculate the chance probability? 2. “Correlation function”: count every pair 1. “Nearest neighbour”: one source for one event formal chance probability ~10 -9 number of tries ~10 4 chance probability ~10 -5 formal chance probability ~10 -4 number of tries ~10 4 chance probability ~1

Black hole neighbourhood: physics gouverned by the black hole mass (safe) upper limit on B size occupied by the field measure black hole mass estimate size constrain field estimate maximal energy

measure black hole mass

acceleration near black hole: no proton acceleration possible for iron, but huge deflection in GMF (no chance to correlate at 3 degrees)

extended structures (jets, lobes)? - detected in 7 of 17 sources - extremely low power - no model-independent B measurements - equipartition: proper place on the Hillas plot - no proton acceleration - Cen A lobes may accelerate light nuclei

Conclusions: updated constraints on the UHECR accelerators AGN=plausible accelerators these are NOT low-power “Auger” AGN! but powerful BL Lacs and radio galaxies “Auger” AGN cannot accelerate protons to observed energies they can accelerate iron, but no correlations then! Cen A = low-power radio galaxy, can accelerate medium-charge nucleiCen A = low-power radio galaxy, can accelerate medium-charge nuclei