CTA and Cosmic-ray Physics

　 Toru Shibata

Aoyama-Gakuin University

(26/Sep/2012)

(1)

capability of CTA for CR-physics

hadronic components (proton, . . . . , iron) ●

leptonic components (electron, positron) ●

(2)

open questions in

All-particle spectrum of cosmic-raysequivalent center of mass energy (GeV)

particle energy (eV/particle)

summarized by R. Engel (KIT)

PROTON satellite

(3)

2-ry (+ 1-ry?)

1-ry + 2-ry (+ 2’-ry?)

p, He, . . , Fe, . . .

p, B, sub-Fe, 10Be, . .

e-, e+,

1-ry

-

indirect obs.

direct obs.

Energy spectra for individual elements

(4)Derbina, V. A., et al., 2005, ApJ, 628, L41

recent results on proton & helium spectraAdriani et al. - Science - 332 (2011) 6025

(5)

~2.75

~2.75

~2.6

really getting harder ?

average mass of cosmic-rays vs. 1-ry energy

proton

iron

Derbina, V. A., et al., 2005, ApJ, 628, L41

lithium

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shower maximum Xmax vs. 1-ry energy Etot

smoothly connecting to direct data ?

Possibility of hadronic spectra with CTA

●

longitudinal profile;

separation between hadrons and e- components

● separation between p, He, . . . . , Fe

L(p-He), M(C-N-O), H(Ne-Mg-Si), VH(Ca-Fe)

transversal profile;

<xmax> (elongation rate)

<r> (lateral spread)

established

difficult, but

probably OK

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Hemberger, Ahronian, et al.26th ICRC(1999)

E/E ~ 50%

proton spectrum

HEGRA;

(9)

● separation between Ne, Mg, . . . . , Fe possible enough

direct cherenkov photons from 1-ry heavy nuclei

Wakely, Kieda, Swordy; ICRC2001

(10)

10TeV 10TeV Mg

(Sitte, ICRC1965)

H.E.S.S.30th ICRC(2007)

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DC ~ 0.1°

EAS ~ 1°

iron spectrum

H.E.S.S.30th ICRC(2007)

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Possibility of leptonic spectra with CTA

on-board observation

all-electron spectrum ( e- + e+ )

● 　 nearby source● 　 maximum accelerable energy● 　 new components● . . . . . . . . .

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1994: Nishimura; possibility of 1-ry electron observation with atmospheric cherenkov telescope

2008: HESS (Ahronian et al.), Phys. Rev. Lett. 101

2011: MAGIC (Tridon et al.)

(Proc. of Towards a Major Atmospheric Cherenkov Detector III, 1, edited by T. Kifune)

(Phys. Rev. Lett. 101)

(Proc. of 32th ICRC, Beijing)

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uncertainty in indirect observation

electron Hadronness=0 electron

(Electronness=1)(Aharonian et al.;arXiv:0811.3894v2, 2009)

(D. B. Tridon; PhD thesis, MPI, 2011

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How about e/ – separation ?

X ~ 15 g/cm2 for e/ !

we should regard the data as an upper limit ?

X ~ 150 g/cm2 for p/Fe

X ~ 5 g/cm2)

CTA

< 300GeV~

< 100GeV~

< 50GeV~

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Possibility of e/ – separation in CTA

Kamioka et al.Astrop. Phys. 6 (1997) 155 - (17)

assuming the separation between hadron and EG (e+)is established, how about between e and

J () = Jeast- Jwest

-components subtracted

but, even if possible, the energy rangeof e+ will be limited within 50-100GeV

_

(e- +e++) (e+ + e- + e-+)

moon shadow with geomagnetic field

Amenomori et al.arXiv:0707.332v (2007)

e+-e- separation: much more hopeful than p-p separation -

remark:

p/p ~ 10-4

e+/e- ~ 0.2

-around 100GeV

~ 20% up ?

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positron fraction

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(preliminary)

Conclusion:

CTA will bring us also fruitful data on chargedcomponents, both hadronic and leptonic ones, in the very high energy region where direct on-board experiments can not cover.

Multi- wavelength with various elements, , e-, e+, p, He, . . . . , sub-Fe, Fe

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