Nachweismethoden der DM

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹

Gravitationslinsen Rotationskurven

Direkter Nachweis der DM

( Elastische Streuung an Kernen) Indirekter Nachweis der DM

( Annihilation der DM in Materie-Antimaterie)

Nachweismethoden der DM

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²

• 95% of the energy of the Universe is non-baryonic

23% in the form of Cold Dark Matter

• Dark Matter enhanced in Galaxies and Clusters of Galaxies but DM widely distributed in halo->

DM must consist of weakly interacting and massive particles -> WIMP‟s

• Annihilation with <σv>=2.10^-26 cm³/s, if thermal relic

From CMB + SN1a + surveys

DM halo profile of galaxy cluster from weak lensing

If it is not dark It does not matter

What is known about Dark Matter?

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³

Thermische Geschichte der WIMPS

Thermal equilibrium abundance Actual abundance

T=M/22

Comoving number density

x=m/T

Jungmann,Kamionkowski, Griest, PR 1995

WMAP -> h²=0.1130.009 ->

<v>=2.10^-26 cm³/s

DM nimmt wieder zu in Galaxien:

1 WIMP/Kaffeetasse 10⁵ <ρ>.

DMA (ρ²) fängt wieder an.

T>>M: f+f->M+M; M+M->f+f T<M: M+M->f+f

T=M/22: M decoupled, stable density (wenn Annihilationsrate ^ Expansions- rate, i.e. =<v>n(x_fr)  H(x_fr) !)

Annihilation in leichtere Teilchen, wie

Quarks und Leptonen -> 0‟s -> Gammas!

Einzige Annahme: WIMP = thermisches Relikt, d.h. im thermischen Bad des frühen Universums erzeugt.

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ⁴

How do particles annihilate?

~ ~

e+

e-

q q

LEP collider:

e+e- annihilation

~ ~

~ ~





e e e

photon annihilation

In CM: Eq=Ee

monoenergetic quarks

from monoenergetic leptons Quarks fragment into jets, mostly light mesons:π+,π-,π⁰ π⁰ decays 100% in 2 photons

So as many photons as charged particles from annihilation

On average: 37 photons pro annihilation into quarks at LEP

Spectral shape VERY WELL MEASURED

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ⁵

DM Annihilation in Supersymmetrie

Dominant

 +   A  b bbar quark pair B-Fragmentation bekannt!

Daher Spektren der Positronen, Gammas und Antiprotonen bekannt!



















 f

f

f f

f f

Z Z W

W

^ ⁰

~ f

A Z

Galaxie = Super B-Fabrik mit Rate 10⁴⁰ x B-Fabrik

≈37 gammas

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ⁶

Indirect Dark Matter Searches

Annihilation products from dark matter annihilation:

Gamma rays

(EGRET, FERMI)

Positrons

Antiprotons

e+ + e-

(ATIC, FERMI, HESS, PAMELA)

Neutrinos

e-, p drown in cosmic rays?

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ⁷

Pamela, arXiv:1001.3522v1

PAMELA Positron excess

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ⁸

Origin?

Depends on whom you ask!

My assumption:

|Data>= a_p->0 |Background> + a_DMA |DMA>

+ a_sec |SNR> + a_local |SNR(x)> + a_pulsar |Pulsar>

Unitarity must be fulfilled. However, each component has enough uncertainty

to saturate observations

For details: WdB, AIP Conf.Proc.1200:165-175,2010.

arXiv:0910.2601 [astro-ph.CO]

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ⁹

AMS: large magn. spectrometer with redundant particle ID

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹⁰

Testflight 1998 AMS installed on ISS in May,2011

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹¹

AMS-02 from CERN to Cape Canaveral on 26.08.2010 Loading the 7.5 tons at Geneva airport

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹²

GALPROP Antiprotons Donata et al. [0810.5292]

Antiprotons: saturated by background?

GALPROP (with and without) convection has deficit of antiprotons. Darksusy and others (which only look into charged particles, no gamma rays) can saturate data.

Pamela

Gebauer and WdB,arXiv:0910.2027

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹³

Propagation of charged cosmic rays (CR)

Present models use isotropic

propagation, i.e. same diffusion constant in halo and disc.

This does not allow for

significant convection, since CR„s do not return to disc->

too little secondary production from CR hitting gas in disc

HOWEVER, significant

convection observed by ROSAT CRs propagation can be

described by diffusion and convection, very much like a drop of ink inside streaming water (with water

velocity=convection velocity)

Radiaactive clocks like ¹⁰Be determine time from source to Sun (10⁷ yrs) Need slow

diffusion in disc, but particles in halo drift to outer space with convection

With convection little flux of charged particles from DMA, since particles drift away.

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹⁴

Present models: isotropic propagation

Is this right?

Isotropic propagation leads to

“propagation enhancement”:

of charged particles: trapping of charged

particles in “leaky” Galaxy for a long time->

Flux of gamma rays from DMA 

Flux of antiprotons in such propagation models, Although we KNOW from LEP that fragmentation gives many more photons than antiprotons

Not nessarily!

CONVECTION = negligible with isotropic

propagation in contrast to observation

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹⁵

Diffuse gamma rays

Great advantage of pointing to the source and propagation is

„straightforward“ without dependence on magnetic field and diffusion,

which plagues charged particles.

Astrophysical point sources can be

pinpointed and subtracted.

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹⁶

Sun

disc

Basic principle for indirect dark matter searches

R Sun

bulge

disc

From rotation curve:

Forces: mv²/r=GmM/r²

or M/r=const.for v=cons.

and (M/r)/r²

1/r²

for flat rotation curve

Expect highest DM density IN CENTRE OF GALAXY

IF FLUX AND SHAPE MEASURED IN ONE DIRECTION, THEN FLUX AND SHAPE FIXED IN ALL (=120) SKY DIRECTIONS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

R₁

THIS IS AN INCREDIBLE CONSTRAINT, LIKE SAYING I VERIFY THE EXCESS AND WIMP MASS WITH 180 INDEPENDENT MEAS.

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹⁷

Wie sehen Haloprofile  aus?

1) Erwarte für Galaxie mit flacher Rotationskurve:   1/r

2) Was passiert für r  0?

N-body Simulationen :   1/r „cuspy profile“

Übergang von   1/r

nach 1/r beschrieben durch NFW Profil:

(zuerst von Navarro, Frenk, White veröffentlicht)

Aber viele Rotationskurven zeigen eher   konst, wenn r  0 (isothermisches Profil)

3) Clumps zeigen Einasto-Profil (   1/r

n<1)

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹⁸

Boostfactor by DM clumping

An artist picture of what we should see if our eyes were sensitive to 3 GeV gamma rays: clumps of DM

in diffuse DM halo (from hierarchical growth of galaxy combined with tidal disruption of clumps

 _diff  _DM ^

 _clump  _clump

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ¹⁹

How to calculate DMA flux?

Beitröge von Sub- struktur (Ringe?)

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²⁰

Weber, Thesis, 2010. KIT

Rotation curve Milky Way

Oort limit on local density prevents larger DM contr.

VLBI point

Weber, dB, arXiv:0910.4272

(Hipparcos data)

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²¹ A. Honma et al, PASJ 2007, Astrometry of Galactic Star-Forming Region Sharpless 269 with VERA:Parallax Measurements and Constraint on Outer Rotation Curve at 13 kpc

VERA: VLBI Exploration of Radio Astrometry

VLBI = Very Large

Baseline Interferometry allows very precise parallax measurements.

Maser light from

Molecular Clouds allows

large distance interferometry Measured parallax of 1896as at distance of >5 kpc

over 1 yr-> rotation velocity Japan

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²²

W.dB, M. Weber, arXiv:1011.6323

Weitere VLBI Daten

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²³

Substrudture in HALO PROFILE ?

Motivation for “outer ring”: Monocerus ring of stars (SDSS, 2002), discussed as tidal disruption of Canis Major dwarf AND gas flaring

Motivation for “inner ring”: dust ring

=

Einasto (clumps) (expected from N-body simulations)

inner

ring outer ring

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²⁴

Dust ring at 4 kpc

Inner Ring coincides with ring of dust and H₂ ->

gravitational potential well!

H₂

4 kpc coincides with ring of neutral hydrogen molecules!

H+H->H₂ in presence of dust->

grav. potential well at 4-5 kpc.

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²⁵

The Milky Way and its satellite galaxies

Canis Major

Tidal force  ΔF_G  1/r³

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²⁶

Tidal streams of dark matter from CM and Sgt

CM

Sgt Sun

From David Law, Caltech

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²⁷

Canis Major Dwarf orbits from N-body simulations to fit visible ring of stars at 13 and 18 kpc

Canis Major leaves at 13 kpc tidal stream of

gas(10⁶ M_☉ from 21 cm line), stars (10⁸ M_☉ ,visible), dark matter (10¹⁰ M_☉, EGRET)

Movie from Nicolas Martin, Rodrigo Ibata

http://astro.u-strasbg.fr/images_ri/canm-e.html

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²⁸

Core of Canis Major Dwarf just below Galactic disc

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ²⁹

Tidal disruption of Sagittarius

Movie from Kathryn Johnston (Wesleyan University ) http://astsun.astro.virginia.edu/~mfs4n/sgr/

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³⁰

N-body simulation from Canis-Major dwarf galaxy

prograde retrograde

Observed stars

R=13 kpc

Canis Major (b=-15⁰)

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³¹

Gas flaring in the Milky Way

no ring

with outer ring

P M W Kalberla, L Dedes, J Kerp and U Haud, arXiv:0704.3925

Gas flaring needs also outer ring with mass of 2.10¹⁰M_☉!

Mass in ring few % of total

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³²

Woher erwartet man Untergrund?

Quarks from WIMPS

Quarks in protons

Background from nuclear interactions (mainly p+p-> π0 + X ->  + X inverse Compton scattering (e-+  -> e- + )

Bremsstrahlung (e- + N -> e- +  + N)

Shape of background KNOWN if Cosmic Ray spectra of p and e- known

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³³

Data driven analysis of gamma ray data (publicly available from NASA archive) Idea:

Fit known shapes of 3 main components:

Inverse Compton:(IC)  CR electron density x ISRF

Bremstrahlung:(BR)  CR electron density x gas density P_CRP_Gas scattering:(⁰)  CR proton density x gas density

Main unknowns: CR electron density CR proton density

(both measured locally, i.e. at a single point in Galaxy)

Alternative to data driven analysis:

compare data with Galactic Propagation Model

Best publicly available model: GALPROP (Moskalenko,Strong…)

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³⁴

Background mainly in disk

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³⁵

Usual astrophysicist‟s search strategies

Particle physicist: get rid of model

dependence by DATA DRIVEN calibration

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³⁶

Instrumental parameters:

Energy range: 0.02-30 GeV Energy resolution: ~20%

Effective area: 1500 cm² Angular resol.: <0.5⁰

Data taking: 1991-1994 Main results:

Catalogue of point sources Excess in diffuse gamma rays

EGRET (Energetic Gamma Ray Experiment Telescope.) Data publicly available from NASA archive

EGRET excess

Hunter et al. 1997

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³⁷

Experimentelle Schwierigkeiten

Experiment hat kein Magnetfeld

Dadurch werden zwei Spuren (e+e.) von konvertiertes Gamma ab ca. 5 GeV kaum getrennt.

Gamma unterscheidet sich von Elektron nur noch durch doppelt so hohe Ionisationsverluste.

Lokale Punktquellen, wie Pulsare, müssen abgezogen werden.

Kein großes Problem, wenn man über genügend große

Raumbereiche integriert (diff. Beitrag prop. Raumwinkel) Bei hohen Energien erzeugt elektromagnetischer Schauer

„backsplash“ von Teilchen, die Vetozähler setzen und dadurch Ereignis verwerfen.

Resultat: Experimente widersprechen sich, z.B. EGRET vs FERMI Oder FERMI Reprocessing P6 vs. P7,

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³⁸

Untergrund + DM Annihilation beschreiben Daten

Blue: background uncertainty

Background + DMA signal describe EGRET data!

Blue: WIMP mass uncertainty 50 GeV

70

Brems . WIMPS IC





. IC

W. de Boer et al., 2005

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ³⁹

FERMI measures GeV gamma rays + electrons

e+ e^–



Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ⁴⁰

FERMI diffuse spectra from Galactic centre

without DMA with DMA

60 GeV DMA neutralino

0+IC+BR

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ⁴¹

Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 ⁴²

Es gibt interessante Hinweise für Teilchencharakter der DM:

a) Überschuss an Gammastrahlung von EGRET gemessen (aber FERMI misst weniger und Konsistenz mit

Antiprotonenfluss steht nach aus, abhängig vom Propagationsmodell)

b) Jährliche Modulation der Signale in Libra/DAMA (aber inkonsistent mit anderen Experimenten)

c) Überschüsse in Positronen (PAMELA Satellit)

(aber Pulsare oder andere Quellen bieten gute Lösung)

Zusammenfassung