gravitationslinsen rotationskurven direkter nachweis der ... · gravitationslinsen rotationskurven...
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Gravitationslinsen
Rotationskurven
Direkter Nachweis der DM
Nachweismethoden der DM
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 1
Direkter Nachweis der DM( Elastische Streuung an Kernen)
Indirekter Nachweis der DM ( Annihilation der DM in Materie-Antimaterie)
• 95% of the energy of the Universe is non-baryonic23% in the form of Cold Dark Matter
• Dark Matter enhanced in Galaxies and Clusters of Galaxies but DM widely distributed in halo >
From CMB + SN1a + surveys
If it is not darkIt does not matter
What is known about Dark Matter?
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 2
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
DM halo profile of galaxycluster from weak lensing
It does not matter
Thermische Geschichte der WIMPS
Thermal equilibrium abundance
Actual abundance
er d
ensi
ty G
riest
, PR
199
5
WMAP -> h2=0.1130.009 -><v>=2.10-26 cm3/s
T>>M: f+f->M+M; M+M->f+fT<M: M+M->f+fT=M/22: M decoupled, stable density(wenn Annihilationsrate Expansions-rate, i.e. =<v>n(xfr) H(xfr) !)
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 3
T=M/22Com
ovin
g nu
mb
x=m/T
Jung
man
n,K
amio
nkow
ski,
DM nimmt wieder zu in Galaxien:1 WIMP/Kaffeetasse 105 <ρ>.DMA (ρ2) fängt wieder an.
Annihilation in leichtere Teilchen, wieQuarks und Leptonen -> 0’s -> Gammas!
Einzige Annahme: WIMP = thermischesRelikt, d.h. im thermischen Bad des frühen Universums erzeugt.
How do particles annihilate?
~~e+
e-
q
q
LEP collider:e+e- annihilation ~~
~~
e
ee
photon annihilation
In CM: Eq=Eemonoenergetic quarks
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 4
monoenergetic quarksfrom monoenergetic leptons
Quarks fragment into jets,mostly light mesons:π+,π-,π0
π0 decays 100% in 2 photonsSo as many photons as charged particlesfrom annihilationOn average: 37 photons pro annihilation into quarks at LEPSpectral shape VERY WELL MEASURED
DM Annihilation in Supersymmetrie
f
f
f
f
f
f
ZW0
f~ A Z
≈37 gammas
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Dominant + A b bbar quark pair
B-Fragmentation bekannt!Daher Spektren der Positronen,Gammas und Antiprotonen bekannt!
ZW 0
Galaxie = Super B-Fabrik mit Rate 1040 x B-Fabrik
Indirect Dark Matter Searches Annihilation products fromdark matter annihilation:
Gamma rays(EGRET, FERMI)
Positrons (PAMELA)
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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
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Origin?
Depends on whom you ask!
My assumption:
|Data>= ap->0 |Background> + aDMA |DMA>+ asec |SNR> + alocal |SNR(x)> + apulsar |Pulsar>
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sec local 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
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AMS installed on ISS in May,2011
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Testflight 1998
AMS-02 from CERN to Cape Canaveral on 26.08.2010
Loading the 7.5 tons at Geneva airport
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GALPROP Antiprotons Donata et al. [0810.5292]
Antiprotons: saturated by background?
Pamela
B,ar
Xiv:0
910.
2027
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GALPROP (with and without) convection has deficit ofantiprotons. Darksusy and others (which only look into charged particles, no gamma rays) can saturate data.
Geba
uer
and
WdB
Propagation of charged cosmic rays (CR)
This does not allow for significant convection, since CR‘s do not return to disc->too little secondary productionfrom CR hitting gas in disc
HOWEVER, significant convection observed by ROSAT
CRs propagation can be
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 13
Present models use isotropic propagation, i.e. same diffusion constant in halo and disc.
p p gdescribed 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 particlesin halo drift to outer spacewith convectionWith convection little flux of charged particles from DMA, since particles drift away.
Present models: isotropic propagation
Isotropic propagation leads to “propagation enhancement”:of charged particles: trapping of chargedparticles in “leaky” Galaxy for a long time->
Flux of gamma rays from DMA Flux of antiprotons in such propagation models,
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 14
Is this right?
Flux of antiprotons in such propagation models,
Although we KNOW from LEP that fragmentationgives 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,hi h l h d i l
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 15
which plagues charged particles.
Astrophysical point sources can be pinpointed and subtracted.
Sundisc
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
R1
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 16
Expect highest DM densityIN CENTRE OF GALAXY
IF FLUX AND SHAPE MEASURED INONE DIRECTION, THEN FLUX ANDSHAPE FIXED IN ALL (=120) SKY DIRECTIONS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
THIS IS AN INCREDIBLE CONSTRAINT, LIKE SAYING I VERIFYTHE 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 durchNFW P fil
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 17
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
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 18
An artist picture of what we should see if our eyes were sensitive to 3 GeV gamma rays: clumps of DMin diffuse DM halo (from hierarchical growth of galaxy combined with tidal disruption of clumps
diffDM
clumpclump
How to calculate DMA flux?
Beitrögevon Sub-struktur(Ringe?)
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esis, 20
10. KI
TRotation curve Milky Way
VLBI pointWeber, dB, arXiv:0910.4272
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Web
er, Th
e
Oort limit on local densityprevents larger DM contr. (Hipparcos data
VERA: VLBI Exploration of Radio Astrometry
VLBI = Very LargeBaseline Interferometryallows very precise parallaxmeasurements.Maser light fromMolecular Clouds allowslarge distance interferometry
Japan
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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
large distance interferometry
Measured parallax of 1896asat distance of >5 kpc over 1 yr-> rotation velocity
Weitere VLBI Daten
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W.dB, M. Weber,arXiv:1011.6323
Substrudture in HALO PROFILE ?
= NFW (diffuse)+Einasto (clumps)(expected from N-body simulations)
inner
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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
innerring outer
ring
Inner Ring coincides with ring of dust and H2 ->gravitational potential well!
H2
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 24
Dust ring at 4 kpc 4 kpc coincides with ring ofneutral hydrogen molecules!H+H->H2 in presence of dust->grav. potential well at 4-5 kpc.
The Milky Way and its satellite galaxies
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 25
Canis Major
Tidal force ΔFG 1/r3
Tidal streams of dark matter from CM and Sgt
CMSun
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CM
Sgt
From David Law, Caltech
Canis Major Dwarf orbits from N-body simulationsto fit visible ring of stars at 13 and 18 kpc
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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 Ibatahttp://astro.u-strasbg.fr/images_ri/canm-e.html
Core of Canis Major Dwarf just below Galactic disc
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 28
Tidal disruption of Sagittarius
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 29
Movie from Kathryn Johnston (Wesleyan University )http://astsun.astro.virginia.edu/~mfs4n/sgr/
N-body simulation from Canis-Major dwarf galaxy
serv
ed s
tars
R=13 kpc
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prograde retrograde
Obs Canis Major (b=-150)
Gas flaring in the Milky Way
no ring
P M W Kalberla, L Dedes, J Kerp and U Haud, arXiv:0704.3925
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no ring
with outer ring
Gas flaring needs also outer ring with mass of 2.1010M☉!
Mass in ring few % of total
Woher erwartet man Untergrund?
Quarks fromWIMPS
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Quarks in protons
Background from nuclear interactions (mainly p+p-> π0 + X -> + Xinverse 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 ISRFBremstrahlung:(BR) CR electron density x gas densityPCRPGas scattering:(0) CR proton density x gas density
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 33
Main unknowns: CR electron densityCR proton density
(both measured locally, i.e. at a single point in Galaxy)
Alternative to data driven analysis: compare data with Galactic Propagation ModelBest publicly available model: GALPROP (Moskalenko,Strong…)
Background mainly in disk
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 34
Usual astrophysicist’s search strategies
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Particle physicist: get rid of modeldependence by DATA DRIVEN calibration
I t t l t
EGRET (Energetic Gamma Ray Experiment Telescope.)Data publicly available from NASA archive
EGRET excessHunter et al. 1997
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Instrumental parameters:
Energy range: 0.02-30 GeVEnergy resolution: ~20%Effective area: 1500 cm2
Angular resol.: <0.50
Data taking: 1991-1994
Main results: Catalogue of point sourcesExcess in diffuse gamma rays
Experimentelle Schwierigkeiten
Experiment hat kein MagnetfeldDadurch werden zwei Spuren (e+e.) von konvertiertes Gamma ab ca. 5 GeV kaum getrennt.Gamma unterscheidet sich von Elektron nur nochdurch doppelt so hohe Ionisationsverluste.
Lokale Punktquellen, wie Pulsare, müssen abgezogen werden.
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q g gKein großes Problem, wenn man über genügend großeRaumbereiche 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 FERMIOder FERMI Reprocessing P6 vs. P7,
Untergrund + DM Annihilation beschreiben Daten
Background + DMA signal describe EGRET data!
50 GeV
70MPS
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Blue: background uncertainty Blue: WIMP mass uncertainty
70Brems .
ICWIM
0
IC
0 WIM
PS
Brems .
IC
W. de Boer et al., 2005
FERMI measures GeV gamma rays + electrons
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e+
e–
FERMI diffuse spectra from Galactic centre
without DMA with DMA
0+IC+BR
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DMA60 GeV
neutralino
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Es gibt interessante Hinweise für Teilchencharakterder DM:
a) Überschuss an Gammastrahlung von EGRET gemessen(aber FERMI misst weniger und Konsistenz mit Antiprotonenfluss steht nach aus, abhängig vomPropagationsmodell)
Zusammenfassung
Wim de Boer, Karlsruhe Kosmologie VL, 23.01.2012 42
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)