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)