wim de boer, karlsruhe ppc2007, texas a&m univ., may. 16, 2007 1 the dark connection between...

Wim de Boer, Karlsruhe PPC2007, Texas A&M Univ., May. 16, 2007 1

The dark connection between Canis Major, Monoceros Stream, gas flaring, the rotation curve and the EGRET excess

From EGRET excess of diffuse Galactic gamma rays• Determination of WIMP mass• Determination of WIMP halo (= standard halo + DM ring)

Confirmation of DM ring:• Rotation curve• N-body similation of Canis Major/Monoceros stream• Gas flaring

PREDICTIONS• for LHC (if SUSY)• for direct searches• for solar neutrinos

Ingredientsto this analysis

gamma spectrafor BG + DMASUSY

Particle Physics

Cosmology

Astrophysics

23%DM, thermalhistory of WIMPs annihilationcross sectionGalaxy formation

CosmicsGamma rays

Astronomers

Rotation curveDoughnut of stars at 13 kpcDoughnut of H2 at 4 kpcGas flaring


Thermal History of WIMPs

Thermal equilibrium abundance

Actual abundance

T=M/22Co

mo

vin

g n

um

ber

d

ensi

ty

x=m/TJungmann,Kamionkowski, Griest, PR 1995

WMAP -> h2=0.1130.009 -> <v>=2.10-26 cm3/s

DM increases in Galaxies:1 WIMP/coffee cup 105 <ρ>. DMA (ρ2) restarts again..

T>>M: f+f->M+M; M+M->f+fT<M: M+M->f+fT=M/22: M decoupled, stable density(when annihilation rate expansion- rate, i.e. =<v>n(xfr) H(xfr) !)

Annihilation into lighter particles, likequarks and leptons -> 0’s -> Gammas!Only assumption in this analysis:WIMP = THERMAL RELIC!


Example of DM annihilation (SUSY)

Dominant + A b bbar quark pairSum of diagrams should yield<σv>=2.10-26 cm3/s to getcorrect relic density

Quark-Fragmentation known!Hence spectra of positrons,gammas and antiprotons known!Relative amount of ,p,e+ known as well.

f

f

f

f

f

f

Z

Z

W

W 0

f~

A Z

≈37 gammas


IF DM particles are thermal relics from early universethey can annihilate with cross section as large as <v>=2.10-26 cm3/s which implies an enormous rate of gamma raysfrom π0 decays (produced in quark fragmentation) (Galaxy=1040 higher rate than any accelerator)

Expect large fraction of energetic Galactic gamma rays to come from DMA in this case.Remaining ones from pCR+pGAS-> π0+X , π0->2γ

This means: Galactic gamma rays have 2 componentswith a shape KNOWN from the 2 BEST studied reactionsin accelerators: background known from fixed target exp. DMA known from e+e- annihilation (LEP)

Conclusion sofar


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

EGRET on CGRO (Compton Gamma Ray Observ.)

Data publicly available from NASA archive


R

Sundisc

Basic principle for indirect dark matter searches

R

Sun

bulge

disc

From rotation curve:

mv2/r=GmM/r2=cons.and(M/r)/r2

1/r2

for const. rot.curve

EXPECT MOST OF DMIN CENTRE OF GALAXY

Divergent for r=0?NFW profile1/rIsothermal profile const. 1/(r2+a2)

IF FLUX AND SHAPE MEASURED INONE DIRECTION, THEN FLUX ANDSHAPE FIXED IN ALL (=180) SKY DIRECTIONS for a given halo profile!

R1

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


Background + signal describe EGRET data!

Blue: background uncertainty

Background + DMA signal describe EGRET data!

Blue: WI MP mass uncertainty

50 GeV

70

I CI C

WdB, C. Sander, V. Zhukov, A. Gladyshev, D. Kazakov,EGRET excess of diffuse Galactic Gamma Rays as Tracer of DM, astro-ph/0508617, A&A, 444 (2005) 51


Analysis of EGRET data in 6 sky directions

A: inner Galaxy (l=±300, |b|<50)B: Galactic plane avoiding AC: Outer Galaxy

D: low latitude (10-200)

E: intermediate lat. (20-600)F: Galactic poles (60-900)

A: inner Galaxy B: outer disc C: outer Galaxy

D: low latitude E: intermediate lat. F: galactic poles

Total 2 for all regions :28/36 Prob.= 0.8 Excess above background > 10σ.


Fits for 180 instead of 6 regions180 regions:80 in longitude 45 bins4 bins in latitude 00<|b|<50

50<|b|<100

100<|b|<200

200<|b|<900 4x45=180 bins >1400 data points. Reduced 2≈1 with 7% errorsBUT NEEDED IN ADDITION to 1/r2 profile, substructurein the form of 2 doughnut-likerings in the Galactic disc!

ONE RING COINCIDES WITHORBIT FROM CANIS MAJORDWARF GALAXY which losesmass along orbit by tidal forces

OTHER RING coincides with H2 ring


R

x y

z

2002,Newberg et al. Ibata et al, Crane et al. Yanny et al.

1/r2 profile and ringsdetermined from inde-pendent directions

xy

xz

Expected Profile

v2M/r=cons.(M/r)/r2

1/r2

for const.rotation

curveDivergent for

r=0?NFW1/r

Isotherm const.1/(r2+a2)

Dark Matter distribution

Halo profile

Observed Profile

xy

xz

Outer Ring

Inner Ring

bulge

tota

lDM

1/(r2+a2) halodisk

Rotation Curve

Normalize to solar velocity of 220 km/s

abg


N-body simulations show: Progenitor of 13 kpc ring = Canis Major Dwarf just below Galactic disc


Canis Major Dwarf orbits from N-body simulationsto 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 Ibatahttp://astro.u-strasbg.fr/images_ri/canm-e.html


N-body simulation from Canis-Major dwarf galaxy

prograderetrograde

Ob

serv

ed

sta

rsR=13 kpc

Canis Major (lat=-150)

Predicted DM ring from N-bodysimulations, relying only on stars,COINCIDED PERFECTLYwith EGRET excess: • radius of ring 13 kpc• ellipticity = 0.9• angle of major axis -200

• retrograde orbit excluded

Penarrubia et al.astro-ph/0410448 astro-ph/0703601


Excess of DM from Canis Major +tidal stream indeed seen D

ark

matt

er

sig

nal (a

rb.

un

its)

CM

lat.lat.

Factor 3 more signal from region with trailing stream (from comparison of data below and above Galactic disk)


Gas flaring in the Milky Way

no ring

with ring

P M W Kalberla, L Dedes, J Kerp and U Haud, http://arxiv.org/abs/0704.3925

Gas flaring needs EGRET ring!


Enhancement of inner (outer) ring over 1/r2 profile 6 (8).Mass in rings 0.3 (3)% of total DM

Inner Ring coincides with ring of dust and H2 -> gravitational potential well!

H2

4 kpc coincides with ring ofneutral hydrogen molecules!H+H->H2 in presence of dust->grav. potential well at 4-5 kpc.


Bergstrom et al. astro-ph/0603632, Abstract:

we investigate the viability of the model using the DarkSUSY package to compute the gamma-ray and antiproton fluxes. We are able to show that their (=WdB et al) model is excluded by a wide margin from the measured flux of antiprotons.

Problem with DarkSUSY (DS):

1) Flux of antiprotons/gamma in DarkSUSY: O(1) from DMA. However, O(10-2) from LEP data Reason: DS has diffusion box with isotropic diffusion -> DMA fills up box with high density of antiprotons2) More realistic models have anisotropic diffusion. E.g. spiral galaxies have magnetic fields perpendicular to disk-> antiprotons may spiral quickly out of Galaxy. In addition: convection of particles by CR pressure.

Does antiproton data exclude interpretation of EGRET data?


Antiprotons B/C ratio

Preliminary results from GALPROP with isotropic and anisotropic propagation

Summary: with anisotropic propagation you can send charged particleswhereever you want and still be consistent with B/C and 10Be/9Be


8 Physics Questions answered SIMULTANEOUSLY if WIMP = thermal relic

• Astrophysicists: What is the origin of “GeV excess” of diffuse

Galactic Gamma Rays?• Astronomers: Why a change of slope in the galactic rotation

curve at R0 ≈ 11 kpc? Why ring of stars at 13 kpc? Why ring of molecular hydrogen at 4 kpc? Why S-shape in gas flaring? • Cosmologists: How is DM annihilating?A: into

quark pairs

How is Cold Dark Matter distributed?• Particle physicists: Is DM annihilating as expected in

Supersymmetry?

A: DM substructure

A: DM annihilation

A: standard profile + substructure

A: Cross sections perfectly consistent with mSUGRA for light gauginos, heavy squarks/sleptons


Expected SUSY mass spectra in mSUGRA

mSUGRA: common masses m0 and m1/2 for spin 0 and spin ½ particles


Gauge unification perfect with SUSY spectrum from EGRET

With SUSY spectrum from EGRET + WMAP data and start values of couplings from LEP data perfect gauge coupling unification!

Up

date

fro

m A

mald

i,

dB

, F

ürs

ten

au

, P

LB

260

1991

SM SUSY

Also b->s and g-2 agree within 2σ with SUSY spectrum from EGRET

NO FREEPARAMETER


Solar neutrinos and direct DM detection

EGRET?

CDMS

SUN

EG

RET


Clustering of DM

An artist picture of what we should see if oureyes were sensitive to 3 GeV gamma rays and wewere flying with 220 km/s through the DM halo


Objections from:

Astronomers: RC shows we have no DM in GalaxyAstroparticle physicists: tune CR spectra to avoid such “exotic” explanations as DM annihilation But strong breaks in injection spectra needed and no good fit if all 180 sky directions consideredCosmologists: such high ringlike overdensities unlikelyParticle physicists: you discover new particles at accelerators, not by watching the skyConventional models CANNOT explain simultaneously:• spectrum of gamma rays in ALL directions, • 1/r2 profile of excess, • shape of rotation curve, • ghostly ring of stars at 13 kpc, • ring of H2 at 4 kpc, • gas flaring


Summary

>10σ EGRET excess shows intriguing hint that:

WIMP is thermal relic with expected annihilation into quark pairs

SPATIAL DISTRIBUTION of annihilation signal is signature for DMAwhich clearly shows that EGRET excess is tracer of DM by fact thatone can CONSTRUCT ROTATION CURVE FROM GAMMA RAYS.

DM becomes visible by gamma rays from fragmentation(30-40 gamma rays of few GeV pro annihilation from π0 decays)

Results rather model independent, since only KNOWN spectral shapes of signal and background used, NO model dependent calculations of abs.fluxes.Different models or unknown experimental problems may change boost factor and/or WIMP mass, BUT NOT the distribution in the sky.

DM interpretation strongly supported N-body simulation of Canis Major dwarf and its tidal streams coinciding with the EGRET excess

EGRET shows lots of DM mass in the tidal streams -> GAS FLARING


Summary on WIMP searches

Indirect detection: (SPACE EXPERIMENTS)

intriguing hint for signals from DMA for 60 GeV WIMP from gamma rays

Direct detection: (UNDERGROUND OBSERVATORIES) expected to observe signal in near future

IF we are not in VOID of clumpy DM halo

Direct production:(ACCELERATORS (LHC 2008-2018)): cannot produce WIMPs directly (too small cross section), BUT IF WIMPs are Lightest Supersymmetric Particle (LSP) THEN WIMPs observable in DECAY of SUSY particles

IF EVERY METHOD measures SAME WIMP mass, then PERFECT.In this case Dark Matter is the supersymmetric partner of the CMB!

wim de boer, karlsruhe ppc2007, texas a&m univ., may. 16, 2007 1 the dark connection between...

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