In collaboration with Kohei Hayashi , Masahiro Ibe, Miho N. - PowerPoint PPT Presentation

(In preparation) Koji Ichikawa In collaboration with Kohei Hayashi , Masahiro Ibe, Miho N. Ishigaki, Shigeki Matsumoto and Hajime Sugai. 1 PPP2015, Kyoto, Sep. 14-18, 2015

(In preparation) Koji Ichikawa In collaboration with Kohei Hayashi , Masahiro Ibe, Miho N. Ishigaki, Shigeki Matsumoto and Hajime Sugai. 2 PPP2015, Kyoto, Sep. 14-18, 2015

Dark Matter Search Indirect Detection Direct Detection DM SM DM SM Collider Production 3

Signal Target Extra dSphs Galaxy/ Cluster Milky-Way Galaxy 10 Mpc 100 kpc 8.5 kpc Charged CRs 4

Current (slightly old) observational limit Wino DM annihilation cross section 5

Current (slightly old) observational limit Wino DM annihilation cross section 6

Current observational limit 7

Dwarf spheroidal galaxies dSphs: 1. Neighbor galaxies: 10~100kpc 2. Large Mass to Luminosity ratio = DM rich 3. Fewer gas containment Ultra-faint Classical SDSS-II 8 arXiv:0908.2995v6 [astro-ph.CO]

Current observational limit 9

Current observational limit 10

Signal Flux Astrophysics Factor Particle Physics Factor (J-factor)   Z  Error: 1-10 % level f WW , ZZ , , Large uncertainty: Next Slide Cirelli et al. (2012) Hryczuk and Iengo (2012) 11 arXiv:1012.4515 [hep-ph] arXiv:1111.2916v4 [hep-ph]

Astrophysical Factor     DM Density profile 1 2 Cusp ( r / r ) ( 1 r / r ) s s s      1 2 Cored ( 1 r / r ) ( 1 r / r ) s s s Stellar Density Profile: ν(r) Jeans equation   2 (Theory) 2 (obs) for stars l.o.s l.o.s Fit Geringer-Sameth et al., arXiv:1408.0002 12

Astrophysical Factor     DM Density profile 1 2 Cusp ( r / r ) ( 1 r / r ) s s s      1 2 Cored ( 1 r / r ) ( 1 r / r ) s s s Stellar Density Profile: ν(r) Jeans equation   2 (Theory) 2 (obs) for stars l.o.s l.o.s Fit Classical: Well-determined Ultra-faint: Not well-determined. Prior dependence Conservative? 13

Hidden Systematics … Prior Bias?/Cut? ex: Non Spherical? => 0.2 0.4 uncertainty Foreground Contamination? Member Star Sampling Bias?

Hidden Systematics … Draco Prior Bias? /Cut? ex: Non Spherical? Segue1 => 0.2 0.4 uncertainty Foreground Contamination? Member Star Sampling Bias? Martinez et al., arXiv: 0902.4715

Hidden Systematics … Prior Bias?/ Cut? ex: Non Spherical? Geringer-Sameth et al., => 0.2 0.4 uncertainty arXiv:1408.0002 Foreground Contamination? Bonnivard et al., arXiv: 1407.7822 Member Star Sampling Bias?

Hidden Systematics … Spherical Prior Bias?/Cut? ex: By K. Hayashi (Preliminary) Non Spherical? Axisymmetric: Hayasi and Chiba., arXiv: 1206.3888 => 0.2 0.4 uncertainty Foreground Contamination? Member Star Sampling Bias? Bonnivard et al., arXiv: 1407.7822

Prime Focus Spectroscopy FoV 1.3 deg (diam) with 2394 Fiber MMFS (M. G. Walker et al,. (2007)) 18

Prime Focus Spectroscopy FoV 1.3 deg (diam) with 2394 Fiber MMFS (M. G. Walker et al,. (2007)) 19

Prime Focus Spectroscopy More accurate DM profile #Obs Star (<V) #Obs Star (<V) estimation ↓ More Robust constraints by M. Ishigaki

Strategy 1. Mock Observable: (R, v, Metalicity, Luminosity) = dSph Stellar + Foreground dSph Stellar Mock  Boltzmann Equation under DM profile Foreground Mock  Besancon Model (Robin+ (2003)) 2. Detector Convolution:  1. fix: dv = 3.0km/s 3. Fit: (DM profile, anisotropy, dSph stellar profile, dSph v, foreground norm + metalicity)  Fit to (v, r) probability density. 21 Walker+, AJ 137 (2009)

Strategy 1. Mock Samples ρ DM (r), ν star (r) => f(r,v) Cuddeford (1991) 1. Mock Observable: (R, v, Metalicity, Luminosity) = dSph Stellar + Foreground dSph Stellar Mock  Boltzmann Equation under DM profile Foreground Mock  Besancon Model (Robin+ (2003)) 2. Detector Convolution:  1. fix: dv = 3.0km/s 3. Fit: (DM profile, anisotropy, dSph stellar profile, dSph v, foreground norm + metalicity)  Fit to (v, r) probability density. 22 Walker+, AJ 137 (2009)

Strategy Fit without Foreground 1. Mock Observable: (R, v, Metalicity, Luminosity) = dSph Stellar + Foreground dSph Stellar Mock  Boltzmann Equation under DM profile Foreground Mock  Besancon Model (Robin+ (2003)) 2. Detector Convolution:  1. fix: dv = 3.0km/s 3. Fit: (DM profile, anisotropy, dSph stellar profile, dSph v, foreground norm + metalicity)  Fit to (v, r) probability density. 23 Walker+, AJ 137 (2009)

Strategy 2. Foreground Besancon Model Prob. Density 1. Mock Observable: Robin+ (2003) (R, v, Metalicity, Luminosity) Obs = dSph Stellar + Foreground 3. Fit dSph Stellar Mock  Boltzmann Equation under DM profile Foreground Mock  Besancon Model (Robin+ (2003)) 2. Detector Convolution:  1. fix: dv = 3.0km/s 3. Fit: (DM profile, anisotropy, dSph stellar profile, dSph v, foreground norm + metalicity)  Fit to (v, r) probability density. 24 Walker+, AJ 137 (2009)

Strategy 2. Foreground Besancon Model Ursa Minor Like Prob. Density 1. Mock Observable: Robin+ (2003) (R, v, Metalicity, Luminosity) 700 w FG Obs = dSph Stellar + Foreground 3. Fit dSph Stellar Mock  Boltzmann Equation under DM profile N = 300 Foreground Mock  Besancon Model (Robin+ (2003)) 700 2. Detector Convolution:  1. fix: dv = 3.0km/s 3. Fit: True (DM profile, anisotropy, dSph stellar profile, dSph v, foreground norm + metalicity)  Fit to (v, r) probability density. 25 Walker+, AJ 137 (2009)

Foreground Contamination Outer Region = FG dominant How to Reduce FG stars? ~ 10 % Contamination 30 < N Mem < 100 26 Bonnivard et al., arXiv:1506.08209

Foreground Contamination Outer Region = FG dominant How to Reduce FG stars? ~ 10 % Contamination Cut: 1. Velocity … The most effective 2. Color… Not Bad 3. Chemical Component… Degenerate 4. Others? 27

Foreground Contamination Outer Region = FG dominant How to Reduce FG stars? ~ 10 % Contamination Cut: 1. Velocity … The most effective 2. Color… Not Bad 3. Chemical Component… Degenerate 4. Others? 28

Foreground Contamination Outer Region = FG dominant How to Reduce FG stars? ~ 10 % Contamination Cut: 1. Velocity … The most effective 2. Color… Not Bad 3. Chemical Component… Degenerate 4. Others? 29

Foreground Contamination Outer Region = FG dominant How to Reduce FG stars? ~ 10 % Contamination Cut: 1. Velocity … The most effective 2. Color… Not Bad 3. Chemical Component… Degenerate 4. Others? 30

Foreground Contamination Outer Region = FG dominant How to Reduce FG stars? ~ 10 % Contamination Cut: 1. Velocity … The most effective 2. Color… Not Bad 3. Chemical Component… Degenerate 4. Others? 31

Summary • Indirect detection is essential for DM search. • Gamma-ray observation of dSph can give robust constraints on the DM annihilation cross section. • Investigation of stellar kinematics is important. • PFS will play a crucial role. 32

Thank You ! Koji Ichikawa In collaboration with Kohei Hayashi , Masahiro Ibe, Miho N. Ishigaki, Shigeki Matsumoto and Hajime Sugai. 33 PPP2015, Kyoto, Sep. 14-18, 2015