Is there
an alternative
to the cosmological
concordance ?
Only one direct evidence for a
accelerating
Universe:
Supernovae
Hubble diagram
Only one direct evidence ...
BUT...
CMB
CMB
Alternative to the
Concordance Model:
No Λ ...
non power law model
extra mass components:
- neutrinos
- quintessence w ∼ 0
C.M.B.
Blanchard, Douspis, Rowan-Robinson, Sarkar 2003
σ8 then LSS !
Dark energy is NOT requested by WMAP nor by LSS...
Hubble Constant
H0 from gravitational
time delay (Kochanek)
48±3 km/s/Mpc
H0 from SZ :
55-60 km/s/Mpc
(Carlstrom)
Clumping : 25% less...
At this level the
Cosmological Constant
seems the best
to bet on...
...but X-ray Clusters
provide
robust evidence in favor of an
Einstein-de Sitter
Universe!
Ωm
From X-ray Clusters
Number evolution
Principle:
Growth rate of linear
perturbations:
M, z) = A(z, Ωm,...) M, 0)
Principle
Oukbir, Blanchard, 1992, A&A, 262, L21
Principle
Blanchard & Bartlett, 1998, A&A, 332, L49
XMM
Ω-Project
X-ray properties of distant SHARC
clusters
for Cosmology
Z ≈ 0.6
X
M
M
R
X
J
1
1
2
0
XMM Lx-Tx evolution
+ local
◊ XMM
◊ Chandra
Conclusion on evolution:
remarkable convergence
β
Lx/Tx) = Lx/Tx)z = 0(1+z)
z
with β = 0.65 ± 0.28
in full agreement with Chandra (Vikhlinin et al, 2002),
ASCA (Sadat et al., 1998; Novicki et al., 2003....)
D.Lumb et al., 2003
Ωm
From X-ray Clusters
Vauclair et al, 2003
A&A 412, L37
Number counts:
∼300 clusters with
z > 0.3
Method:
RDCS: 50 deg²
fx ≈ 3. 10-14 erg/s/cm²
MACS: 22 000 deg²
fx ≈ 10-12 erg/s/cm²
Likelihood analysis:
r
P
y
r
a
n
i
m
i
l
e
(Vauclair et al., 2004, in
preparation)
Ωm = 0.97 ± 0.125 ± 0.11
Ωm
From X-ray Clusters
Baryon Fraction evolution
in the XMM -project
(Sadat et al., 2004, submitted)
Baryon Fraction
(non)evolution as a test of
Chandra
m
Baryon Fraction @ z = 0
∆ = 2000
Baryon Fraction @ z = 0.6
∆ = 2000
Baryon Fraction @ z = 0.6
Internal structure
is complex...
Baryon Fraction @ z = 0.6
∆ = 2000
Baryon Fraction @ z = 0.6
∆ = 1000
Baryon Fraction @ z = 0.6
∆
v
... favors high Ωm !
Conclusions ?
Strong Evolution in the abundance of x-ray
clusters appears from all existing surveys in a
very consistent way.
This provides a strong argument in favor of
a high matter density...
Consistent with fb evolution ...
Yet an other
degeneracy?
GM/r + ...
GM/r /(1+z)
Tx
i.e. ~ forget gravity...
T
Kill the Mass-Temperature Relation :
2/3
M
Concordance works !
Breaking the degenracy...
T
GM/r /(1+z)
2
/(1+z)
Testable... i.e.
-1
T/
2
1/(1+z)
Conclusions I
Strong Evolution in the abundance of x-ray
clusters appears from all existing surveys in a
very consistent way.
This provides a strong argument in favor of
a high matter density...
Consistent with fb evolution ...
Consistent with fb amplitude ...
Conclusions II
Relaxing this conclusion will require a major
revision of standard scaling of M-T (z)
i.e. Tx ≠ GM/r
New cluster (astro-)physics ?
No sign of it in observed clusters...
i.e. Einstein de Sitter favored...
Conclusions III
A high matter density would imply
extra mass component, but not necessarily
a cosmological constant
ΩXm ≈ 0.1