Dark MatterDark MatterDark MatterDark Matter
Mathieu Langer
Evidence
Possibilities
Detection ?
Evidence
Possibilities
Detection ?
(Many thanks to Gianfranco Bertone,Institut d’Astrophysique de Paris)
Cosmological parameters : status
• Combination of ‘independent’ data
• Universe spatially flat :
‘Cosmological Constant’ : ~ 0.7
‘Matter’ : ~ 0.3
(rem : baryons ~ 0.04)
First Evidence : Velocity dispersion of galaxies in clusters
Fritz Zwicky, 1933
Coma cluster of Galaxies
Motions require more than Motions require more than 100100 times more mass than visible! times more mass than visible!
Galactic rotation curves
Vera Rubin, 1970s
Rotation curves & Dark Matter
2* circ *
2
( )m v Gm M r
r r
Image UV GALEX, A. Gil de Paz, 2006
Degeneracy :
disc vs. halo DM
Mass/Luminosity ratio?(Stellar pop. synth.)
DM : density profile ?(simulations,
poorly constrained at centre)
Broeils, 1992, A&A
Dark Matter : Clusters of galaxies againN
GC
720
A 2
029
ROSAT X-Ray
DSS optical
• Image : X emission– X emission is a function of
density n, x ~ n2
– Question: What density profile can give the observed X ray emission ?
Measure of a cluster density profile
Points: Observations
Line: Best Fit
Abell 2319 – Image ROSAT
[millions of light years]
• Procedure:– Identify the cluster centre– Average azimuthally X emission– Fit the emission profile– Deduce the required density
Gravitational lensing
(http://hubblesite.org)
Convergence
Convergence + shear
Abell 2218
First 3D map of DM distribution !
Massey et al., Nature, 7 Janvier 2007
• High fidelity maps of DM distribution on large scales, resolved in angular resolution and depth thanks to the Cosmic Evolution Survey of the HST (2 degrees2)
• Shape of 71 galaxies per arcmin2
shear field total projected mass
• Follow-up observations by VLT, Subaru, Cerro Tololo & Kitt Peak to get the redshifts
• Optical image of merging clusters (here: 1E 0657-558)
• Reconstruct the shear and the convergence (grav. lensing)
• Projected density maps (green contours)
“Direct proof” : the Bullet Cluster
Clowe et al. ApJL 2006
200 kpc
Clowe et al. ApJL 2006
• X-ray image of the same cluster, 1E 0657-558, by Chandra
• Green contours : convergence (prop. to the projected density)
• White contours : peaks of at 68.3%, 95.5% and 99.7% C.L. 200 kpc
Presence of non-luminous gravitating mass !
“Direct proof” : the Bullet Cluster
1% Stars7% Gas in virialised structures
7% Warm/hot gas in IGM
85% DARK MATTER
Baryons
Non-baryonic
Matter census in the Universe
Don’t know what Dark Matter is?
Ask a Particle Physicist!
Kaluza-Klein DM in UED
Kaluza-Klein DM in RS
Axion
Axino
Gravitino
Photino
SM Neutrino
Sterile Neutrino
Sneutrino
Light DM
Little Higgs DM
Wimpzillas
Cryptobaryonic DM
Q-balls
Mirror Matter
Champs (charged DM)
D-matter
Cryptons
Self-interacting
Superweakly interacting
Braneworld DM
Heavy neutrino
NEUTRALINO
Messenger States in GMSB
Branons
Chaplygin Gas
Split SUSY
Primordial Black Holes
…
“Dark Matter” candidates
L. Roszkowski
“WIMPs”!
WIMP : identity file
• Full name : Weakly Interacting Massive Particle– Rem : generic name
• Interactions : gravitational, weak nuclear (i.e. « weaker than weak » cross-sections)
• Mass : high enough so as to be cold today• Life time : stable / sufficiently long to have remained until now • Relic density : Boltzmann equation + freeze-out
• Nature? SUSY? KK Extra-dimensions? New Physics!
27 3 12
χ
3 10 cm .sh
v
SUSY & LSP…• Supersymmetry?
– Extension of the Poincaré algebra:
Q |Boson = |Fermion , Q |Fermion = |Boson{Q, Q} P , [H,Q] = 0
– Unification of gauge couplings, mass hierarchy (Higgs)
– Keep B & L conservation R-parity, R = (-1)3B+L(-1)2S
– SM particles : R = +1 SUSY particles : R = -1
• R-parity conservation ( if )Lightest Supersymmetric Particle stable!
“Natural” candidate for Dark Matter
• MSSM + R-parity Neutralino :
1 2i i i i iB W H H
Extra Universal Dimensions (EUD)
• Kaluza-Klein : extra dimensions
• EUD : all fields propagate in the 5th dim.
Compactification of extra dim. at each pt. of 3D space
Periodical conditions Momentum quantification
+++
G. Bertone, Particle DM: what comes next?, Seminar @ Tuebingen U.
Neutrino TelescopesGamma-ray Telescopes (non-ACT)Gamma-ray Telescopes (ACTs)Direct Detection Exps.Colliders
Fermi PAMELA
HESS
IceCube (South Pole)
VERITAS
MAGIC
CANGAROO
Antares
Baikal
NemoNestor
LHC
Tevatron
Dark Matter — related experiments: 2006 World Census
Soudan Mine
STACEE
MILAGRO
Boulby Mine
CanfrancGran Sasso
FrejusSudbury
GRAPES
PACT
TACTIC TIBET, ARGO-YBJ
Observing Satellites
Background noise, cryogenics, …
Direct detection : Principle & Status
n
Detector (bolometer)
Collision of a WIMP on a nucleus Light Heat Charge
DAMA
CDMS
EDELWEISS
ZEPLIN
Indirect Detections
DM Indirect Detection
Gamma Telescopes • Ground (CANGAROO, HESS, MAGIC, MILAGRO, VERITAS)• Space : Fermi (GLAST) satellite • Future Cherenkov Telescope Array?
Neutrino Telescopes • Amanda, IceCube• Antares, Nemo, Nestor• Km3
Antimatter Satellites • PAMELA• AMS-2
Other• Synchrotron• SZ effect• Effects on stars…
Indirect detection : Dark Matter annihilations
Early Universe
X
Today
X
X
X
SM
SM
SM
SM
Rough estimate of the relic density:
Electroweak-scale cross sections can reproduce correct relic density. LSP in SUSY scenarios KK DM in UED scenarios are
OK!!
X = DARK MATTER SM = STANDARD MODEL PARTICLE
-ray flux from the GC
We can conveniently re-write the -ray flux from the GC as
where J contains all information on Astrophysics
and the DM profile is usually parameterised as
Note : density profile at the very centre may be sharper due to central BH
Conserve Mass & Angular Momentum:
sp=
M fiM
*Adiabatic* growth of a Black Hole: BHs as “Annihilation Boosters”!
9-24-
r-
r-sp
An intuitive description of Dark Matter “Spikes”
Bertone & Merritt 2005
Evidence for a Supermassive Black Hole at the Galactic Centre
Genzel et al. 2003
M= 3.6 x 106 Solar Masses
To calculate the fluxes, details of annihilations are required. Neutralino annihilations cross-sections can be obtained numerically (DarkSUSY, microMEGA, etc.)
(E. Nezri et al, 2001)
(Servant & Tait, 2002)
Servant & Tait obtained annihilation cross-sections for B (1) particles. In the non-relativistic limit, dependent only on the B(1) mass.
Annihilation Radiation
SUSY
UED
Predictions for KK dark matter and neutralinos in the case of a NFW profile without central spike. Fluxes are always below the EGRET normalisation, but within the reach of several future experiments.
Possibility of constraining B(1) mass. Importance of the dark matter density profile.
GB, Servant & Sigl 2003
-ray flux from the GCGB, Servant & Sigl, 2003
What about baryonic Dark Matter ??What about baryonic Dark Matter ??
Black Holes? Brown Dwarves? Failed Stars?Black Holes? Brown Dwarves? Failed Stars?
Baryonic Objects of stellar mass or lower Baryonic Objects of stellar mass or lower
(Afonso et al, A&A, 2003)
No "MACHOs" in our GalaxyNo "MACHOs" in our Galaxy
Toy derivation of scalar LagrangianToy derivation of scalar Lagrangian
• Heuristic derivation showing how mass terms appear – infinite tower of KK modes
2
2
in2
Rn
n 0
i(m n)2 in2 im2
R R Rn m n m
n 0 m 0 n 0 m 0
n n n nn 0 n 0
2 n
R
2
R
X x , x e
e in e im e
(J.Virzi, UC Berkeley)