The Dark Matter density MW Components Global density Data: inner - PowerPoint PPT Presentation

The Dark Matter density F. Nesti Problem The Dark Matter density MW Components Global density Data: inner Data: outer Data: masers Fabrizio Nesti Fits Annihilation Local density Universit` a dell’Aquila, Italy Method Data: Sun Data: galaxy DM density Conclusions LNGS, July 5 th 2012 w/ C.F. Martins, G. Gentile, P. Salucci

The Dark Matter Dark Matter? density F. Nesti Problem A number of indirect supporting evidences MW Components (galaxy rotation, cluster velocity dispersion, CMB, LSS) Global density Data: inner Data: outer Data: masers Fits Modify Gravity or Matter (or both) Annihilation Local density Modify Gravity: we look still for a healthy theory Method Data: Sun (I’d say still mainly a theoretical activity) Data: galaxy DM density Dark Matter: still elusive (well, more than Higgs) Conclusions (good to have many search channels) Hints (puzzles) from Direct and Indirect searches? (DAMA, Cogent, CDMS, CRESST, Fermi line(?)) Collisionless? (Bullet cluster) or Collisional? (A520 cluster) (mistery)

The Dark Matter The DM densities density F. Nesti Problem All searches depend on the expected DM density: MW Components In the Solar System Global density Data: inner Data: outer Direct laboratory searches at Earth: Data: masers . . . depend on the local density at earth ρ 0 Fits Annihilation Indirect searches (mainly neutrino annihilation in Sun, Earth) Local density Method . . . depend on accumulated DM which in turn is driven by ρ 0 Data: Sun Data: galaxy DM density Conclusions In the Galaxy Looking for decay or annihilation . . . depend on ρ or ρ 2 along the l.o.s. Both the Local and Galactic DM density are interesting. . .

The Dark Matter Our galaxy density F. Nesti Problem Bulge/bar MW Components (10 10 M ⊙ ) Global density Data: inner Data: outer Stellar disk Data: masers Fits (5–7 × 10 10 M ⊙ ) Annihilation Local density Method Dark Matter halo Data: Sun (10 11–12 M ⊙ ) Data: galaxy DM density Conclusions and subleading Thick disk (older stars up to z ∼ kpc) Stellar halo (globular clusters, old BHB, red, brown dwarfs, etc) (at least up to 80 kpc)

The Dark Matter density F. Nesti Problem MW Components The DM Density profile Global density Data: inner Data: outer Data: masers Fits Annihilation Local density Method Data: Sun Data: galaxy DM density Conclusions

The Dark Matter Component profiles density F. Nesti Problem DM profiles, Einasto, NFW, Burkert, cusped or cored MW Components ρ EIN = ρ H e − (2 /α )( x α − 1) Global density Data: inner EIN ( α = 0 . 17) 10 Data: outer Ρ DM � GeV � cm 3 � NFW Data: masers ρ H BUR Fits ρ NFW = Annihilation 1 x (1 + x ) 2 Local density Method 0.1 ρ H Data: Sun ρ BUR = Data: galaxy (1 + x )(1 + x 2 ) DM density 1 2 5 10 20 50 Conclusions r � kpc � (with x = r / R H , scale radius R H ) Triaxiality? small [OBrien+ ’10] . Smooth? Bulge: pointlike (as seen from r > 2 kpc!) M B = 1 . 2–1 . 7 × 10 10 M ⊙ Disk: biexponential, Σ D = ( M D / 2 π R 2 D ) e − r / R D z 0 = 240pc M D = 5–7 × 10 10 M ⊙ [PR04,juric08,robin08,reyle09] R D = 2 . 5 ± 0 . 2 kpc

The Dark Matter Component profiles density F. Nesti Problem DM profiles, Einasto, NFW, Burkert, cusped or cored MW Components ρ EIN = ρ H e − (2 /α )( x α − 1) Global density Data: inner EIN ( α = 0 . 17) 10 Data: outer Ρ DM � GeV � cm 3 � NFW Data: masers ρ H BUR Fits ρ NFW = Annihilation 1 x (1 + x ) 2 Local density Method 0.1 ρ H Data: Sun ρ BUR = Data: galaxy (1 + x )(1 + x 2 ) DM density 1 2 5 10 20 50 Conclusions r � kpc � (with x = r / R H , scale radius R H ) Triaxiality? small [OBrien+ ’10] . Smooth? Bulge: pointlike (as seen from r > 2 kpc!) M B = 1 . 2–1 . 7 × 10 10 M ⊙ Disk: biexponential, Σ D = ( M D / 2 π R 2 D ) e − r / R D z 0 = 240pc M D = 5–7 × 10 10 M ⊙ [PR04,juric08,robin08,reyle09] R D = 2 . 5 ± 0 . 2 kpc

The Dark Matter All together density F. Nesti Problem 250 MW Components Global density 200 Data: inner Data: outer Data: masers Fits V � km � s � 150 Annihilation TOT Local density Bulge Method Disk 100 Data: Sun DM halos Data: galaxy DM density 50 Conclusions 0 0 R � 20 40 60 80 r � kpc � Would like to constrain V ( r ) to constrain ρ DM . Unlike other galaxies, where we can measure V(r) quite well. . . . . . here situation is much harder.

The Dark Matter The Inner rotational velocities density F. Nesti Problem Rotating HI gas in the inner region MW Components Doppler gives relative speed along the l.o.s. Global density Data: inner Maximum at the tangential point, terminal velocities V T : Data: outer Data: masers Fits V ( r ) = V T ( r / R ⊙ ) + V ⊙ r / R ⊙ Annihilation Local density Inside ∼ 1–2 kpc the bulge/bar structure prevents analysis. Method Data: Sun between 2 and 8 kpc a lot of measures along the arms, with Data: galaxy DM density systematic variations Conclusions 280 260 240 V � r � � km � s � 220 200 180 0 2 4 6 8 r � kpc �

The Dark Matter The Inner rotational velocities density F. Nesti Alvarez90 � 123 McClure_Griffiths&Dickey07 � 761 250 Problem 250 Real data, MW Components 200 200 relative speed Global density 150 150 Data: inner V T ( r / R ⊙ ) Data: outer 100 100 Data: masers 50 50 Fits Annihilation 0 0 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Local density Malhotra � from Kerr86 � � 56 Malhotra � from Weaver & Williams74 � � 40 Method 250 250 Data: Sun Data: galaxy 200 200 DM density 150 150 Conclusions 100 100 50 50 0 0 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Sofue � from Clemens � � 142 Malhotra � from Knapp85 � � 23 250 250 200 200 150 150 100 100 50 50 0 0 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0

The Dark Matter The Outer rotational velocities density F. Nesti Problem Out to ∼ 80 kpc, survey of ‘old’ halo stars, moving randomly. . . MW Components Only l.o.s. speed... need to rely on virial equilibrium Global density Data: inner Data: outer ∼ 3000 Tracers Data: masers Fits Eliminate the ouliers ( | v | > 500 km/s) Annihilation Velocity dispersion ∼ 110 km/s Local density Method Data: Sun Binned: [Brown ’10, Xue ’08] Data: galaxy DM density 160 Conclusions 140 Σ tr � km � s � 120 � � � � � � � � � � � � � � � � 100 � � � � � � � � 80 60 20 30 40 50 60 70 80 r � kpc �

The Dark Matter The Outer rotational velocities density F. Nesti Problem Out to ∼ 80 kpc, survey of ‘old’ halo stars, moving randomly. . . MW Components Only l.o.s. speed... need to rely on virial equilibrium Global density Data: inner Data: outer ∼ 3000 Tracers Data: masers Fits Eliminate the ouliers ( | v | > 500 km/s) Annihilation Velocity dispersion ∼ 110 km/s Local density Method Data: Sun Binned: [Brown ’10, Xue ’08] Data: galaxy DM density Conclusions Fig. 11.— The Galactic sky coverage of the observed BHB stars (red dots) and selected simulated stars (black dots), drawn from Simulation I.

The Dark Matter The Outer rotational velocities cont’d density F. Nesti Each population of tracers, has a measured density ρ i ∝ r − γ i , Problem MW Components Consider (?) virial equilibrium and use Jeans’ Equation: Global density Data: inner Data: outer γ i − 2 β i − ∂ ln σ 2 � � V 2 = σ 2 Data: masers i Fits i ∂ ln r Annihilation Local density Method Unknown velocity anisotropy β i (maybe r dependent) Data: Sun Data: galaxy γ i ≃ 3 . 5–4, for observed populations. DM density Conclusions We can integrate Jeans’ equation, for each model: { V model ( r ) , β i } → σ model ( r ) , i and compare σ model with data for that population. i (Traditionally: derive pseudo-measures of V , w/ great uncertainties.)

The Dark Matter Until 2011: the degeneration density F. Nesti Problem 250 MW Components Global density Data: inner 200 Data: outer Data: masers V � km � s � Fits Annihilation 150 Local density Method TOT Data: Sun Bulge Data: galaxy 100 Disk DM density DM halo Conclusions 1 2 5 10 20 50 r � kpc � Inner: Bulge-Disk compensation Middle: Disk-DM Halo compensation Outer: DM Halo ρ H - R H flat direction and, V ⊙ not fixed → shift up/down.

The Dark Matter Masers in Star forming regions density F. Nesti Problem Parallax from ground based arrays: (angular precision 0.01 mas!) MW Components 0 10 Global density Able to constrain: Data: inner Q3 Q2 Outer Arm Data: outer V ⊙ / R ⊙ ≃ 30 . 2 ± 0 . 3 km / s kpc Data: masers 5 WB89-437 Fits S269 Annihilation m V ⊙ ≃ 239 ± 7 km / s r A s e u s r e P Local density Sagittarius Arm [Brunthaler+ ’11] Sun Method 0 0 y (kpc) Q4 Q1 Data: Sun 9.25 kpc Data: galaxy V ( r ≃ 10kpc) ≃ 240 ± 5 km / s l =75.30 o DM density -5 Conclusions Scutum-Centaurus V ( r ≃ 13kpc) ≃ 244 ± 4 km / s G.C. -10 [Sanna+ ’11] Norma Arm -10 -5 0 5 10 x (kpc) First results only. In the near future more extensive surveys from BeSSeL and VERA.