Physical conditions in potential UHECR accelerators

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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
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• Constraints on astrophysical accelerators
• Hillas plot
• radiation losses
• Particular 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?
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• Constraints on astrophysical accelerators
• Hillas plot
• radiation losses
• Particular 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?
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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
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geometry the Hillas criterion Larmor radius lt
size of accelerator (otherwise lefts the
accelerator)
model-independent
EltZBR
size of the accelerator
maximal energy
magnetic field
charge
Schluter Biermann 1950 Hillas 1984
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the (original) Hillas plot
Hillas 1984
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Boratav et al. 2000
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radiation losses rate of E gain lt rate of E loss
synchrotron
curvature
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radiation losses rate of E gain lt rate of E loss
depend on the mechanism
synchrotron
curvature
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• Limitations due to radiation losses
• disagreement on their importance?
• protons can be accelerated to (3-5)1021 eV
• At energies 1022 eV the cosmic ray primaries
  have
• to be heavy nuclei Aharonyan et al. 2002
• Practically, all known astronomical sources are
• not able to produce cosmic rays with energies
  near few
• times 1020 eV Medvedev 2003

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

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• Different acceleration regimes
• diffusive (shocks)

plot Medvedev 2003
gets a hit from time to time, radiates
synchrotron continuously
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• Different acceleration regimes
• diffusive (shocks)
• gets a hit from time to time, radiates
  synchrotron continuously
• inductive (one-shot)
• synchrotron-dominated losses
• curvature-dominated losses

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• Different acceleration regimes
• inductive (one-shot)

plot Medvedev 2003
is accelerated and radiates continuously
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• 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
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• 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
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• 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)
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updated Hillas plots (plus radiation
constraints) - diffusive acceleration
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updated Hillas plots (plus radiation
constraints) - inductive acceleration,
synchrotron losses
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updated Hillas plots (plus radiation
constraints) - inductive acceleration,
synchrotron losses
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updated Hillas plots (plus radiation constraints)
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• Constraints on astrophysical accelerators
• Hillas plot
• radiation losses
• Particular 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?
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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!

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Auger correlations with AGN
various AGN on the Hillas plot
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Auger correlations with AGN an important detail
how to calculate the chance probability?
list of events
list of sources

• calculate number of pairs source-event in data
• compare with expected from Monte-Carlo
• estimate the chance probability

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Auger correlations with AGN an important detail
how to calculate the chance probability?
list of events
list of sources
number of pairs source-event what if there are
several sources for one event?
1. Nearest neighbour one source for one event
2. Correlation function count every pair
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Auger correlations with AGN an important detail
how to calculate the chance probability?
1. Nearest neighbour one source for one event
formal chance probability 10-9
number of tries 104
chance probability 10-5
2. Correlation function count every pair
formal chance probability 10-4
number of tries 104
chance probability 1
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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
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measure black hole mass
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acceleration near black hole no proton
acceleration
possible for iron, but huge deflection in GMF (no
chance to correlate at 3 degrees)
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• 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

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• Conclusions
• updated constraints on the UHECR accelerators
• AGNplausible 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 nuclei