Galactic cosmic rays propagation and dark matter indirect detection
Timur Delahaye
2/58
Dark matter
3/58
Dark matter detection
Tf~m
χ/20 t ~ 10-8 s
4/58
Outline
● Recent data
● Cosmic ray propagation
● Electrons and positron
● γ rays
5/58
Pamela
Adriani et alii Nature 2009
6/58
Former expectations
7/58
Fermi & ATIC
With the courtesy of 8/58
Florent Dubois
HESS
9/58
Cosmic ray propagation
10/58
Cosmic ray propagation
11/58
Cosmic ray propagation
Primary Primary
12/58
Cosmic ray propagation
Primary Primary
13/58
Cosmic ray propagation
Secondary Secondary
14/58
Cosmic ray propagation
Escaping Escaping
15/58
Cosmic ray propagation
∂t ∂ J =Q
x , E ,t = d 4 N d 3 x d E
JE =bloss - DEE ∂E
J =V c − K ∇
16/58
Cosmic ray propagation
∂t −∇⋅ K ∇ −V c
∂E bloss − DEE ∂E =Q x , E ,t + boundary conditions
Diffusion parameters
Maurin et alii ApJ 2001
18/58
Energy losses
Adiabatic expansion Bremsstrahlung
Inverse Compton Ionisation
Synchrotron
19/58
Energy losses
20/58
Secondary positrons (and electrons)
21/58
Propagation influence
T.D,. Lineros, et alii
A&A 2009
22/58
Proton flux influence
T.D,. Lineros, et alii
A&A 2009
23/58
Crosssection influence
T.D,. Lineros, et alii
A&A 2009
24/58
Secondary e+
25/58
Primary sources
e+
Pulsar
e γ e
p α ν
SNR
γ
?
DM
e+ e p p
γ ν
26/58
Source term
Q E = v
m
2 f E Q E =
m
f E 27/58
Source term
Q E = v
m
2 f E Q E =
m
f E 28/58
Dark matter distribution
29/58
Dark matter distribution
T.D,. Lineros, Donato,
Fornengo, &
Salati
PRD 2008
30/58
Source term
Q E = v
m
2 f E Q E =
m
f E 31/58
Annihilation channel
32/58
Annihilation channel
T.D,. Lineros, Donato,
Fornengo, &
Salati
PRD 2008
33/58
Boost factor
● Particle physics
● Sommerfeld effect
● Resonances
● Cosmology
● Nonthermal production
● Modification of cosmology
● Astrophysics
● Clumps
● Caustics
34/58
Clumps
Via Lactea 2
Diemand et alii
35/58
A nearby clump
Brun, T.D,.
Diemand, Profumo
& Salati PRL 2009
36/58
Antiprotons
Maurin,
Donato, Brun, T.D,. & Salati PRL 2008
37/58
Dark matter problems
Dark matter can explain the data
● Boost factor
● Antiproton data
BUT
Naturalness ?
38/58
A deeper look at astrophysical electrons and positrons
39/58
Primary sources
e+
Pulsar
e γ e
p α ν
SNR
γ
?
DM
e+ e p p
γ ν
40/58
Astrophysical sources
Q x , E ,t =Q0 E− e−E /Ec x−xst −t s
41/58
Distant sources
42/58
Nearby sources
+ radio
brightness and spectral index
T.D., Lineros, Lavalle et alii.
A&A in press
43/58
Results: e+
T.D., Lineros, Lavalle et alii.
A&A in press
44/58
Results: e
T.D., Lineros, Lavalle et alii.
A&A in press
45/58
Results: e + e+
T.D., Lineros, Lavalle et alii.
A&A in press
46/58
Results: e+ fraction
T.D., Lineros, Lavalle et alii.
A&A in press
47/58
Recent data
● Astrophysical sources can account for all recent data
● There is too much freedom to dismiss a dark matter interpretation nevertheless
48/58
γ rays : a new hope
for dark matter?
49/58
Inverse Compton and dark matter
Boehm, T.D. & Silk, submitted to PRL
50/58
π0 sky
Fiasson, T.D., Salati,
& Pohl, in prep.
51/58
Other γ ray components
● Bremsstrahlung
● Inverse Compton
● Synchrotron
electrons
52/58
Conclusions
● Fast analytical methods allow to size all sources of uncertainties in current
understanding of cosmic rays.
● Recent data can be explained by
astrophysical sources without fine tuning the parameters and Dark matter explanation
seems unnatural.
● Dark matter indirect detection is promising but difficult.
53/58
Bonus
54/58
Proton flux
55/58
Proton flux
56/58
Proton flux
57/58
Proton flux
58/58
Local sources
