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Interpretation of cosmic ray spectrum above the knee
measured by the Tunka-133 experiment
L.G. Sveshnikova, L.A. Kuzmichev, E.E. Korosteleva, V.A. Prosin, V.S. Ptuskin
et al Moscow State University Skobeltsyn Institute of Nuclear physics
Outline
• Problems
• Tunka 25,133 method and results
• Comparison with other experiments
• Theoretical model of sources and Emax
• Origin of the Knee and transition region to Metagalactic
• Сonclusions
Figure from V. Ptuskin, V. Zirakashvili, and
Eun-Suk Seo, Astrophysical J. T. 718 p.
31–36. 2010 .
From the theory we can expect the sequence of different types of dominating sources in
different energy intervals and only a small number can accelerate to highest energies
due to high value of required magnetic field and shock speed. Only very specific
conditions of explosions and progenitor’s history allows to get large Emax.
IIp Ibc Ia ? or IIb IIb? GRB?
100 TeV 1PeV 4 PeV 60 PeV
Transition from one type of dominating sources to other should reveals itself
as a features in spectrum: knee , dip, peak.. So precise measurement of all
particle spectrum and of partial nuclei spectra continue to be very important
task.
Problem
PeV accelerated particle escape from SNR at 10-100 years after explosion,
so a chance to see directly gamma quanta from pevatron is very small.
R= 1 km
175 optical detectors (EMI 9350) covering an area of 3 km2
In operation since 2009
Tunka-133 a 3 km2 Air Cherenkov Light Array
50 km from Lake Baikal, in Siberia
Single detector: We measure the next parameneters of Cherenkov
photon pulse through 5 ns: Q=c∙Spulse, Amax, dt=, ti time
delay with accuracy nsec
ti
Spulse
Amax
anode:
dinode:
Width of pulse
Lateral distribution is approximated by 4 functions in every shower and Q200 and
steepness parameter b is estimated
A(R) =
A(400)·((R/400+1)/2)-b
A(R) = A(400)·((R/400+a)/(a+1))-b
A(R) = Akn·exp((Rkn-
R)·(1+3/(R+2))/R0)
A(R) = Akn·(Rkn/R)c
Recalculation from Cherenkov light flux Q200 to the primary energy E0
E0 = A·Q200g
g = 0.94
CORSIKA simulation:
protons
iron nuclei
Zenith angles: 0°, 30°, 45°
As a measure of energy we use the
Cherenkov light flux density at a core
distance of 200m - Q(200). It was found
from CORSIKA.
First method of Xmax reconstruction by parameter b
∆Xmax = 2767 - 3437∙log10(bA-2),
g∙cm-2
Dependence of the relative
EAS maximum position Xmax
on log (b − 2)
Dis
tance to the m
axim
um
of show
er
Second method of Xmax reconstruction from width of pulse,(400m), “width-distance method”
The -method uses the sensitivity
of the pulse width at some fixed
core distance to the position of the
EAS maximum.
This function was constructed
on the basis of CORSIKA
simulation
the value of ( 400) is connected
with the thickness of the
atmosphere between the detector
and Xmax
(Xmax = X0/cos − Xmax) by the
expression:
Xmax = C − D · log e f f (400).
Dis
tance to the m
axim
um
of show
er
Log Pulse Width at 400 m
Best fit (solid) for two different energy bins. The lines correspond to:
proton (red dash), helium (pink), nitrogen (dagreen) and iron (blue).
Xmax distribution in every energy bin was fitted as a superposition of weighted
elemental distribution of 4 groups: p, He, CNO and Fe.
For this analysis, partial Xmax distributions were simulated using CORSIKA 7.35
(2013) with QGSJETII-04/GHEISHA (S.N.Epimakhov et al. (Tunka Collaboration),
33th ICRC, Julym 2013.397 ID=0326.)
Distribution of Xmax in every energy interval is converted to partial spectra P, He, CNO, Fe
Experimental data
3 winter seasons of operation 2009-2010 , 2010-2011, 2011-2012
1000 houre of good wether observation
~ 6 000 000 triggeres
For the analysis of mass composition only events with
θ ≤ 40°, Rcore < 500 m:
~ 170 000 showers with E0 > 6·1015 eV – 100% efficiency
~ 60 000 events with E0 > 1016 eV
~ 600 events with E0 >1017 eV
Doi
http://dx.doi.org/10.1016/j.nima.2013.09.018
1 knee hardening 2 knee
In press
http://dx.doi.org/10.1016/j.nima.2013.09.018
Spectra of P, He, CNO, Fe components
Systematic errors are large !!
Kascade Grande W.D. Apel et al. [KASCADE-Grande Collaboration], Phys.
Rev. D 87, 402 081101(R) (2013)
Tunka: http://dx.doi.org/10.1016/j.nima.2013.09.018
Comparison of light and heavy components with Kascade – Grande : nuclei separation by Xmax in
Tunka versus muon content of showers in KG
Comparison with other experiments: agreement
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-1,00
-0,75
-0,50
-0,25
0,00
0,25
0,50
Structure=F(E)/AE-3-1
Str
=F
(E)/
AE
3-1
E, GeV
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109
106
1,5x106
2x106
2,5x106
3x106
IxE
3.0 m
-2 s
-1 sr-
1 G
eV
1.7
5
En, GeV
106
107
108
109
-0,4
-0,2
0,0
0,2
0,4
Structure F(E)/AE-3 -1
Str
uctF
(E)*
E1
E GeV
Tibet 3 models
Gamma Ice Top 2013
Tunka 133(2012), Kascade-Gr.
Comparison:
Common features
1. Sharpness and position of the knee at 4 PeV
2. Sharpness and position of the inverse knee (hardening) at 20 PeV
3. Sharpness and position of the second knee at 100 or 300 PeV
(Tunka: 2 knee `300 PeV, Kascade Gr ~ closer to 100 PeV)
Features: knees, dips, peaks
How they can be produced?
32 ICRC, 2012, Beijing
100
101
10-2
10-1
100
Hoerandel 1 TeV : P+He=60%: 0.20,0.40, 0.13,0.13,0.13
Hoerandel 1 TeV : P+He=60%: 0.30,0.30, 0.13,0.13,0.13
In
teg
ral sp
ectr
um
by Z
:N>
Z
Z
d=lg(IFe/Itot)/lg 26 ~ d ~0.6 (if Fe 13%) d~ 0.5 (if Fe~20%)
Regidity dependent cutoff: Emax(Z)=ZEmax(H)
Change of gamma
by 0.5-0.6
corresponds to
“normal
composition”
Integral abundance I(>Z)
d=0.5-0.6
Normal
composition – one
of the main
signature of
acceleration
at the forward
shock front of
SNR
Bump or dip or knee at the boundary of two
decreasing and increasing components: :
107
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1010
1011
105
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107
3
.0
FxE
E (GeV)
d e m o d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o d e m o
Galactic CR- Extra Galactic CR
signature
Basic model of composition and Emax of Galactic sources at high energies:
sources are spread
continuously in space
and time Additionally we introduced:
1) a stochastic nature of sources , using Green function formalism
2) the condition that Emax for Core Collapsed SN is distributed from 1 0TeV to 3 PeV
3) Actual nearby sources from gamma catalogues
L. Sveshnikova, O. Strelnikova, V. Ptuskin. Astropart. Phys. 2013, 50-52, pp
33-46
V. Ptuskin, V. Zirakashvili, and Eun-Suk
Seo, Astrophysical J. T. 718 p. 31–36.
2010
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109
1010
102
103
104
105
106
ATIC-2; Tibet QGSJet
Tunka-133; Kascade-Grande
Calculation
F(E
)*E
2.7
m-2 s
-1 s
r-1 G
eV
1.7
E (GeV)
CC_SNR
SN IIb
SN Ia
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108
1E-4
1E-3
0,01
0,1
1
E GeV
C=d=3, =4
dgam=2, om=6
Source spectrum :Numerical simulations of diffusive shock acceleration
in SNRs. From V.N.Zirakashvili, V.S.Ptuskin :
http://arxiv.org/pdf/1109.4482.pdf
Spectra of particles
produced in the
supernova remnant
during 100 000 yr.
injected at the forward
shock (thick solid line ), ,
spectrum of ions injected
at the reverse shock (thick
dashed line)
1)The first version of explanation of the inverse knee at 20 TeV was presented in ECRS 2012: Knee is provided mainly by CR accelerated in SN_Ia or other group of sources with similar Emax. We can directly obtain the chemical composition if we suggest the nearly same slopes for species. In this case hardening at 20 PeV is produced by increase of heavy nuclei.
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1010
1011
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Si
CNOHe
P
Z
Z14
Z
Z
Tunka133 Tunka25 Kascade Gr. Kascade
EASTOP Tibet Augergv Hires1M3 Hires2
Fe_Tunka Fe Kasc. Gr.
F(E
) E
3.0
E, GeV
Z1
All
It was shown: 1) Composition is enriched by Fe: P+He(~55-60) CNO(10%) Si-Ca(~10%),Fe (~20-25%) (Dark blue points) 2) Source spectrum has a sharp cutoff
2013:New data from Tunka-133: the ratio of Fe was decreased essentially, so the hardening after 20 PeV is
caused by the appearance of a new component
105
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109
106
107
F(E
) E
3.0
E, GeV
new Fe
P+HE
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
After subtracting the contribution of CR provided the knee we have the rest that reminds most of all
well known “dip” model
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1010
1011
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107
F(E
) E
3.0
E, GeV
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
P+He
HIRES
rest
Extragalactic CR: “Dip model” (V. Berezinsky. (2013) arXiv:1301.0914 V. Berezinsky, et al Phys. Lett. B 612,147 (2005)+ “magnetic horizon effect” (M. Lemoine, Phys. Rev. D
71, 083007 (2005), R. Aloisio and V. Berezinsky, ApJ 625, 249 (2005)]
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1010
1011
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107
[12] g=-2.7 Emax=10^22ev
Calculations [15] , B=2 nG
Mod.2, lc=100, ns=10^-5
Mod. 3, lc=30, ns=10^-6
Mod. 4, lc=100, ns=10^-5
Mod. 1, lc=300, ns=10^-5
Approximations in Fig.1
1 2 3
3
.0
FxE
E (GeV)
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
Low energy behaviour depends on mean strength of magnetic field B0=0.3-3 nG,
coherence length lc ~ 30- 300 kpc, source density ns=10^-5-10^-6
the diffusion time
of particles with
energy E <
10^17 eV from
the closest
sources
(50−100Mpc)
becomes longer
than the age of
the Universe.
K. Kotera and M. Lemoine
arXiv:0706.1891v2
Signature of e+e- pair-
production in interaction of
UHE protons with CMB
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109
1010
1011
EASTOP [18] Tibet [17] KASCADE[19]
Tunka 25,133 [1] KASC. Gr. 2012 [3] Ice Top [5]
Model prediction
Sum of Gal. + Extragal.: 3 2 1 P+He
Extragal. : 3 2 1
Galactic : All P+He Z>6 Z>14 Z>20
F(E
) E
3.0
m
-2 s
-1 s
r-1G
eV
2
E, GeV
Galactic - Extragalactic
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108
109
1010
1011
106
107
EASTOP [18] Tibet [17] KASCADE[19]
Tunka 25,133 [1] KASC. Gr. 2012 [3] Ice Top [5]
Model prediction
Sum of Gal. + Extragal.: 3 2 1 P+He
Extragal. : 3 2 1
Galactic : All P+He Z>6 Z>14 Z>20
F(E
) E
3.0
m-2 s
-1 s
r-1G
eV2
E, GeV
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
The all particle spectrum, light component and heavy component measured in Tunka-
133 can be described with the model when knee is produced by the special class
of sources with ~ same Emax and approximately normal chemical composition, the
extragalactic protons arises between 10^16 ÷ 10^17 eV thus stressing the hardening
of all particle spectrum at 20 PeV, the contribution of extragalactic protons reaches 50%
of all particles around 200-300 PeV.
CONCLUSION I
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109
1010
0
1
2
3
4
5 Kascade[24] MSU [25]
ATIC2[22] Tunka 25,133 [2] [1]
Jacee [23] Auger [26] Ice Top
Model prediction 3, 2, 1,
<
ln A
>
E (GeV)
Tunka 133 - <lnA> -black full stars (2012); open stars (2013)
75% P+25% He
Nuclear component
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107
108
109
106
2x106
3x106
4x106
5x106
Heavy
Model prediction
Galactic : Z>6 Z>14 Z>20
F(E
) E
3.0
m
-2 s
-1 s
r-1
GeV
2
E, GeV
Red-new 11June
Fe
Z>6
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
These points, if they
are not of methodical
reasons, are beyond
the model. The
systematic errors are
very large.
Defects 1. This model gives the dip only at proton or light
composition of extragalactic CR !!! It assumes
rightness of Hires and TA data, Auger data are in
strong contradiction.
2. Dip and GZK cutoff can be modified by
discreteness in sources distribution, by source
local overdensity or deficit and by different value
of Emax (V. Berezinskii)
Transition region from the numerous SNRs to the SNRs or other sources providing the knee is
a very interesting region
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1010
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104
105
106
ATIC-2; Tibet QGSJet
Tunka-133; Kascade-Grande
Calculation
F(E
)*E
2.7
m-2 s
-1 s
r-1 G
eV
1.7
E (GeV)
CC_SNR
SN IIb
SN Ia
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107
108
109
1010
105
106
107
Tunka P
Atic2, A
rgo P+He
IxE
3.0 m
-2 s
-1 s
r-1
GeV
2.0
En, GeV
Atic2 a
ll
Tunka All
Tunka P+He
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
P +He: Atic2, Argo, - Tunka – the same slope as in all particle spectrum
All Nuclei, Fe nuclei : Atic2->Tunka 133
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1010
104
105
106
107
IxE
3.0 m
-2 s
-1 sr-
1 G
eV
2.0
E0, GeV
allNuc
Atic
N>CNO
N>Fe
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108
109
1010
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106
107
Ix
E3.0 m
-2 s
-1 s
r-1 G
eV
2.0
En, GeV
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
CNO: from Atic 2 to Tunka-133
Atic2
Atic2
Conclusion II
1. Group of sources providing the knee look like
SNRs, because source spectrum and composition
are in agreement with the standard model of
acceleration by SNR forward shock.
2. But in the region 100-4000 PeV – transition region
from usual SNRs to rare sources providing the
knee, we believe some new features in spectrum
and composition will be found.
3. In 2014-2015 the first 20 stations of Hiscore –
Tunka non imaging Cherenkov array starts to
measure HE gammas and background cosmic rays
Nearby sources
Cas A – a very good candidate
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101010
5
106
107
3
.0
FxE
E (GeV)
CAS A (SNR of IIb type - nearest )
Source spectrum -2.02
Emax=210^17 eV
twice power for CR prod.
Light composition
Fe~2%
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o
Many unusual properties from (J.
Vink. arXiv:1112.0576v2 ) J
1. Cas A must have been a Type IIb
SNR, similar to SN1993J
2. Progenitor main sequence mass of
18±2M⊙.
3. Strong bipolarity referred to as “the
jet”.
4. Best explained with a binary star
scenario, in which a high mass loss is
caused by a common envelope phase.
L.G. Sveshnikova, E.E. Korosteleva, L.A. Kuzmichev, et al, Journal of
408 Physics: Conference Series, 409, 1 (2013)012062; arXiv:1303.1713.
Tunka2013
Tunka 2011
•
• 1) Sources spectrum: ~ 1.7-2.01, • Emax ~ z(23)1017 , • very light composition P+He~95%, Fe<2%
• 2) Closest sources should be at distance ~2-4
kpc, T < 100 ky
• 3) One source with usual power is enough, may be Cas A??? SNRIIb type
Contribution of nearby sources around the knee
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1010
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106
Vela Jr (0.3 kpc 0.7 ky)
ATIC-2; Tibet QGSJet
Tunka-133; Kascade-Grande
Calculation
F(E
)*E
2.7
m-2 s
-1 s
r-1 G
eV
1.7
E (GeV)
HB9
Cygnus Loop
HB21
Vela Jr. (0.7 kpc 1.7 ky)
d e m o d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o d e m o
d e m o d e m o d e m o d e m o d e m o
We could not exclude the “single source”
But only Vela Jr. can provide the structure around the knee and
only if : 1) Emax=F(Temission) 2) D~0.3 kpc, T~0.7 ky
It’s very difficult to
obtained high Fe content
around 10^17 eV.
Bachground sources also
have high Fe content
Thank you !
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109
1010
105
106
107
Atic2, A
rgo P
+He
IxE
3.0 m
-2 s
-1 s
r-1
Ge
V2
.0
En, GeV
HeJac 2.63
Atic2 a
ll
Tunka All
Tunka P+He
103
104
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106
107
108
109
1010
104
105
106
107
IxE
3.0 m
-2 s
-1 sr-
1 G
eV2.
0
En, GeV
allNuc
Atic
N>CNO
N>Fe
Fe Kascade
102
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104
105
106
107
108
109
1010
105
106
107
IxE
3.0 m
-2 s
-1 s
r-1 G
eV
2.0
En, GeV
CNO
Mass composition