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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 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.
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 (PAMELA)
Antiprotons (PAMELA)
e+ + e- (ATIC, FERMI, HESS, PAMELA)
Neutrinos (Icecube, no results yet) e-, p drown in cosmic rays?
Wim de Boer, Karlsruhe
Kosmologie VL, 23.01.2012 8
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]
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
Gebaue
r and
WdB,a
rXiv:0
910.2
027
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/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)
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
diffDM
clumpclump
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 1896as 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
= NFW (diffuse)+ 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 ΔFG 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
Obse
rved s
tars
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 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…)
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.
ICWIM
PS
0
IC
0
WIM
PS
Brems.
IC
W. de Boer et al., 2005
Wim de Boer, Karlsruhe
Kosmologie VL, 23.01.2012 40
FERMI diffuse spectra from Galactic centre
without DMA with DMA
DMA 60 GeV
neutralino
0+IC+BR
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
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