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Neutrino cosmology. DESY, 30 September 2008 Julien Lesgourgues (CERN & EPFL). MAIN STREAM DM = CDM + 3 flavor neutrinos, with 2 or 3 massive eigenstates 2 unknown “cosmological parameters”: S m n , IH or NH - PowerPoint PPT Presentation
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DESY, 30 September 2008
Julien Lesgourgues (CERN & EPFL)
MAIN STREAM
DM = CDM + 3 flavor neutrinos, with 2 or 3 massive eigenstates
2 unknown “cosmological parameters”: m, IH or NH
detectable negligible
SIDE WAYS
Sterile, non-thermal, coupled, decaying, mass-varying, …
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Effect of Effect of neutrino neutrino
massmass
Effect of neutrino massEffect of neutrino mass Background effect: parameter different from cdm
(also DM today, but radiation in the past)
e.g. increase with fixed dm
decrease cdm
postpone M/R equality
change CMB peak height (and position) and
shape of matter power spectrum P(k)
non-degenerate effect for flat CDM
Effect on perturbations: free-streaming slows down
structure formation
Perfect versus free-streaming fluidPerfect versus free-streaming fluid Perfect fluid = strongly coupled particles with bulk velocity
(in the linear regime: single-valued velocity field)
Free-streaming particles = collisionless particles with f(x,p,t) ≈ f(p,t)
x
p
x
p|v| = |p| /m = velocity dispersion
CDM (WIMPS) in the approximation v << c
HDM (light neutrinos) with 0.01 < v/c < 1
Free-streaming scaleFree-streaming scale
distances
time
a
inflati
on
RADIATIONDOMINATION
eq
MATTERDOMINATION
acausal
causal
RH
perturb
ation wavelength
Free-streaming scaleFree-streaming scale
distances
time
a
inflati
on
RADIATIONDOMINATION
eq
MATTERDOMINATION
acausal
causal
RH
perturb
ation wavelength
maximumcomoving f.s.s.
free-streaming scale
(10-4 eV < m < 1 eV)
nrheavy light
Effect of neutrino massesEffect of neutrino masseson (linear) structure formationon (linear) structure formation
m + H m = 4G m m
expansion gravitational force
Below critical scale, neutrinos contribute to expansion but not
to gravitational force: m(a) slows down, [d ln m / d ln a – 1]
m
. ..
cdm
b
metric
a
J.L.
& S
. Past
or,
Physi
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eport
s [a
stro
-ph/0
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]J.L.
& S
. Past
or,
Physi
cs R
eport
s [a
stro
-ph/0
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94
]
Free-streaming and structure Free-streaming and structure formationformation
cdm
b
metric
a
1-3/5fa
J.L.
& S
. Past
or,
Physi
cs R
eport
s [a
stro
-ph/0
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94
]J.L.
& S
. Past
or,
Physi
cs R
eport
s [a
stro
-ph/0
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94
]
Free-streaming and structure Free-streaming and structure formationformation
(f = /m)
A. characteristic shape of matter power spectrum today
Signature of massive neutrinos on Signature of massive neutrinos on P(k)P(k)
P(k) = m2
(today)
kk
Light neutrinos step-like suppression
-8f-8f (from 3% to 60% (from 3% to 60% for 0.05eV to 1eV)for 0.05eV to 1eV)
B. linear growth factor
Signature of massive neutrinos on Signature of massive neutrinos on P(k)P(k)
P(k,a)/a2
=(1+z)2 P(k,z)
kk
sCDM no linear growth factor
sCDM (no DE, no m)
B. linear growth factor
Signature of massive neutrinos on Signature of massive neutrinos on P(k)P(k)
P(k,a)/a2
=(1+z)2 P(k,z)
kk
DE+CDM scale-independent linear growth factor
sCDM (no DE, no m)
DE+CDM (no m)
B. linear growth factor
Signature of massive neutrinos on Signature of massive neutrinos on P(k)P(k)
P(k,a)/a2
=(1+z)2 P(k,z)
kk
DE+CDM+m scale-dependent linear growth factor
sCDM (no DE, no m)
DE+CDM+HDM
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currentcurrentobservationobservation
s s till 2007:
best constraints from free-streaming
since WMAP-5yr: background effect
better seen
future: free-streamingmore powerful
mass bounds from 7-parameter fits (MDM = minimal CDM+M)
BoundsBounds o onn neutrino neutrino mass massA
dapte
d f
rom
J.L
. &
S. Past
or,
Physi
cs R
eport
s 0
6
(95% CL)
+ SNIa / BAO
+ Ly
mass bounds from 7-parameter fits (MDM = minimal CDM+M)
BoundsBounds o onn neutrino neutrino mass massA
dapte
d f
rom
J.L
. &
S. Past
or,
Physi
cs R
eport
s 0
6
(95% CL)
+ SNIa / BAO
+ Ly
CMB only WMAP5Dunkley et al. 08
mass bounds from 7-parameter fits (MDM = minimal CDM+M)
BoundsBounds o onn neutrino neutrino mass massA
dapte
d f
rom
J.L
. &
S. Past
or,
Physi
cs R
eport
s 0
6
WMAP5 + BAO (SDSS, 2dF) + + SNIa (SNLS, ESSENCE) Komatsu et al. 08
+ SNIa / BAO
+ Ly
+ background (dA, dL)
(95% CL)
mass bounds from 7-parameter fits (MDM = minimal CDM+M)
BoundsBounds o onn neutrino neutrino mass massA
dapte
d f
rom
J.L
. &
S. Past
or,
Physi
cs R
eport
s 0
6
WMAP3 + SDSS-LRG/BAO + 2dF + SNIaHannestad et al. 07, Kristiansen et al. 07
+ SNIa / BAO
+ Ly
+ galaxy power spectrum
(95% CL)
mass bounds from 7-parameter fits (MDM = minimal CDM+M)
BoundsBounds o onn neutrino neutrino mass massA
dapte
d f
rom
J.L
. &
S. Past
or,
Physi
cs R
eport
s 0
6
WMAP3 + SDSS-LRG/BAO + 2dF + SNIaHannestad et al. 07, Kristiansen et al. 07
+ SNIa / BAO
+ Ly
+ galaxy power spectrum
(95% CL)
limited to scales still linear today:
suppression effectin power spectrum P(k)
mass bounds from 7-parameter fits (MDM = minimal CDM+M)
BoundsBounds o onn neutrino neutrino mass massA
dapte
d f
rom
J.L
. &
S. Past
or,
Physi
cs R
eport
s 0
6
WMAP5 + other CMB + SDSS-LRG/BAO + SNIa + SDSS-LyFogli et al. 08
+ SNIa / BAO
+ Lyman- forest
(95% CL)
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futurefuturetechniques techniques
Weak lensing: galaxy Weak lensing: galaxy shearshear
Future:Future:many dedicated many dedicated surveys surveys (CFHTLS, DES, SNAP, (CFHTLS, DES, SNAP, Pan-STARRS, LSST, Pan-STARRS, LSST, Dune, …)Dune, …)
Map of gravitational potentialMap of gravitational potentialprojected along line-of-sightprojected along line-of-sight
COSMOSCOSMOS
Massey et al., Nature 05497, 7 january 2007Massey et al., Nature 05497, 7 january 2007
tomographtomographyy
Weak lensing: CMB Weak lensing: CMB deflectiondeflection
map of gravitational potentialmap of gravitational potentialprojected along line-of-sight, especially around z~3projected along line-of-sight, especially around z~3
Weak lensing: theoretical Weak lensing: theoretical predictionprediction
Lensing spectrum (= convergence spectrum)expected power spectrum of lensing potential
from sources at z ~ 0.2, 0.6, … 3.0(error for LSST)
from sources at z ~ 1100 (CMB)(error for CMBpol)
linea
r
Song & Knox
[astro-ph/0312175]
Weak lensing: theoretical Weak lensing: theoretical predictionprediction
Lensing potential spectrum
Weak lensing: observation with Weak lensing: observation with PlanckPlanck
JL, Perotto, Pastor, PiatPhys.Rev.D73:045021,2006
Weak lensing: forecastsWeak lensing: forecastsJ.L.
& S
. Past
or,
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LSST
SNAPPlanck+DUNEKitching et al 08
Perotto et al. 06Lesgourgues et al. 05
Song & Knox 2003
Other promising techniquesOther promising techniques ISW effect induced by free-streaming during MD/DED
Detectable with CMB x LSS cross-correlation
Ichikawa & Takahashi 05
Lesgourgues, Valkenburg & Gaztanaga 07
Cluster redshift surveys
Wang et al. 05
21cm surveys
(21cm line emission by residual cosmic hydrogen after reionization)
Wyithe & Loeb 08
=0.006 eV (differentiate NH / IH) Pritchard & Pierpaoli 08
Ly forests in quasar spectra
Gratton et al. 07
Impact of massive neutrinos on Impact of massive neutrinos on
non-linear gravitational non-linear gravitational clusteringclustering
… … is a crucial to understand, in order to:is a crucial to understand, in order to:
- Extend analysis of galaxy / cluster/ cosmic shear surveys to larger kExtend analysis of galaxy / cluster/ cosmic shear surveys to larger k
- Perform proper analysis of Ly-Perform proper analysis of Ly- / BAO / 21cm data / BAO / 21cm data
- Properly extract / interpret CMB foregrounds (thermal SZ)Properly extract / interpret CMB foregrounds (thermal SZ)
- Precisely address small-scale CDM distribution problem (satellites)Precisely address small-scale CDM distribution problem (satellites)
Impact of massive neutrinos on Impact of massive neutrinos on
non-linear gravitational non-linear gravitational clusteringclustering
Brandbyge et al. 0802.3700 [astro-ph]
N-body simulations including thermal velocities
Impact of massive neutrinos on Impact of massive neutrinos on
non-linear gravitational non-linear gravitational clusteringclustering
Saito, Takada, Taruya 0801.0607 [astro-ph]
Semi-analytical method (approximation to one-loop order)
z=0
Impact of massive neutrinos on Impact of massive neutrinos on
non-linear gravitational non-linear gravitational clusteringclustering
Y.Y.Y.Wong 0809.0693 [astro-ph]
Semi-analytical method (one-loop order)
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