nachweismethoden der dm - … · kosmologie vl, 23.01.2012 2 ... ams-02 from cern to cape canaveral...

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



• 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?



Thermische Geschichte der WIMPS

Thermal equilibrium abundance

Actual abundance

T=M/22 Co

mo

vin

g n

um

ber

den

sit

y

x=m/T

Ju

ng

man

n,K

am

ion

ko

wski, G

riest,

PR

1995

WMAP -> h2=0.1130.009 -> <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(xfr) H(xfr) !)

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.



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



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



Indirect Dark Matter Searches

Annihilation products from dark matter annihilation: Gamma rays (EGRET, FERMI)

Positrons (PAMELA)

Antiprotons (PAMELA)

e+ + e- (ATIC, FERMI, HESS, PAMELA)

Neutrinos (Icecube, no results yet) e-, p drown in cosmic rays?



Pamela, arXiv:1001.3522v1

PAMELA Positron excess



Origin?

Depends on whom you ask!

My assumption: |Data>= ap->0 |Background> + aDMA |DMA> + asec |SNR> + alocal |SNR(x)> + apulsar |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]



AMS: large magn. spectrometer with redundant particle ID



Testflight 1998

AMS installed on ISS in May,2011



AMS-02 from CERN to Cape Canaveral on 26.08.2010

Loading the 7.5 tons at Geneva airport



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

Gebaue

r and

WdB,a

rXiv:0

910.2

027



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.



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



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.



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.



Wie sehen Haloprofile aus?

1) Erwarte für Galaxie mit flacher Rotationskurve: 1/r2

2) Was passiert für r 0? N-body Simulationen : 1/r „cuspy profile“) Übergang von 1/r2 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/rn n<1)



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

diffDM

clumpclump



How to calculate DMA flux?

Beitröge von Sub- struktur (Ringe?)



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)



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 1896as at distance of >5 kpc over 1 yr-> rotation velocity

Japan



W.dB, M. Weber, arXiv:1011.6323

Weitere VLBI Daten



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

= NFW (diffuse)+ Einasto (clumps) (expected from N-body simulations)

inner ring outer

ring



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.



The Milky Way and its satellite galaxies

Canis Major

Tidal force ΔFG 1/r3



Tidal streams of dark matter from CM and Sgt

CM

Sgt

Sun

From David Law, Caltech



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



Core of Canis Major Dwarf just below Galactic disc



Tidal disruption of Sagittarius

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



N-body simulation from Canis-Major dwarf galaxy

prograde retrograde

Obse

rved s

tars

R=13 kpc

Canis Major (b=-150)



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



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



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 PCRPGas 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…)



Background mainly in disk



Usual astrophysicist‟s search strategies

Particle physicist: get rid of model dependence by DATA DRIVEN calibration



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



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,



Untergrund + DM Annihilation beschreiben Daten

Blue: background uncertainty

Background + DMA signal describe EGRET data!

Blue: WIMP mass uncertainty

50 GeV

70

Brems.

ICWIM

PS

0

IC

0

WIM

PS

Brems.

IC

W. de Boer et al., 2005



FERMI measures GeV gamma rays + electrons

e+

e–



FERMI diffuse spectra from Galactic centre

without DMA with DMA

DMA 60 GeV

neutralino

0+IC+BR



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

nachweismethoden der dm - … · kosmologie vl, 23.01.2012 2 ... ams-02 from cern to cape canaveral...

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