The science objectives for CALET Kenji Yoshida (Shibaura Institute of Technology) for the CALET Collaboration

Introduction August 16, nd ICRC (Beijing) 2 Major goals in cosmic-ray study: To make clear the cosmic-ray origin, acceleration and propagation mechanisms One of the most important unresolved problems in astrophysics: Nature and origin of dark matter What the dark matter is made of => CALET for all-sky electron, gamma ray, and nuclear components observations on the JEM-EF of the ISS to study these scientific objectives Other scientific objectives: B.Rauch, Capability of the CALET experiment for measuring elemental abundances of galactic cosmic ray nuclei heavier than nickel (Z=28), ID690, OG1.5 K.Yamaoka, The CALET Gamma-ray Burst Monitor (CGBM), ID839, OG2.5

Identification of electron sources August 16, nd ICRC (Beijing)3 Some nearby sources, e.g. Vela SNR, might leave unique signatures in the electron energy spectrum in the TeV region (Kobayashi et al. 2004) => Identification of the unique signature from nearby SNRs such as Vela in the electron spectrum by CALET Simulated electron energy spectrum of the CALET for 5yr observations from a SNR scenario model (Kobayashi et al. 2004)

Anisotropy of electrons August 16, nd ICRC (Beijing)4 Expected electron intensity distributionExpected anisotropy with energy => Identifiable anisotropy toward nearby SNRs such as the Vela Vela  ~ 10%

Gamma ray observations August 16, nd ICRC (Beijing) 5 Vela pulsar Geminga pulsar Simulated CALET gamma-ray all sky map for 3yr (>10GeV) => Gamma-ray all sky survey for 10GeV-10TeV region by CALET Extra-galactic diffuse gamma-ray spectra CALET Detection limit of Galactic diffuse gamma rays Electron origin proton origin

Indirect dark matter search by electrons August 16, nd ICRC (Beijing) 6 2yr (BF=40) or 5yr (BF=16) Simulated e + +e - spectrum for 2yr from Kaluza-Klein dark matter annihilations with m=620GeV and BF=40 Simulated e + +e - spectrum for 2yr from decaying dark matter for a decay channel of D.M.-> l + l - with m=2.5TeV and  = 2.1x10 26 s => CALET has a potential to detect electron + positron signals from dark matter annihilation/decay (A.Ibarra et al. 2010)

Indirect dark matter search by gamma rays August 16, nd ICRC (Beijing) 7 Simulated gamma-ray line spectrum for 2yr from neutralino annihilation toward the Galactic center with m=820GeV, a Moore halo profile, and BF=5 Simulated extra-galactic gamma-ray spectrum for 2yr from decaying dark matter for a decay channel of D.M.-> l + l - with m=2.5TeV and  = 2.1x10 26 s => CALET has a potential to detect gamma-ray signals from dark matter annihilation/decay with the excellent energy resolution of 2% (A.Ibarra et al. 2010) EGRET

Nuclear components observations August 16, nd ICRC (Beijing) 8 => Confirmation of the spectral hardening and the spectral changing around the knee Expected P and He spectra with a power-law index of Expected B/C with a diffusion coefficient of D 0 E^  (  =0.45) => Severe restriction on the propagation models

Summary Unique signatures of the electron spectrum in TeV region Anisotropy of electrons toward the nearby sources August 16, nd ICRC (Beijing) 9 => Identification of nearby cosmic-ray electron sources by the CALET electron observations in 10GeV – 20TeV Gamma-ray point sources, Galactic and extra-galactic gamma- ray diffuse emission => All-sky survey by high-energy gamma rays in 10GeV – 10TeV with CALET What is the dark matter made of => Indirect dark matter search by the CALET hybrid observations of electrons and gamma rays Cosmic-ray propagation mechanisms => Severe restrictions by CAELT nuclear components observations in several 10GeV – 1000TeV