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L. Perivolaropouloshttp://leandros.physics.uoi.gr
Department of Physics
University of Ioannina
Open page
S. Nesseris, LP, astro-ph/0610092, astro-ph/0611238
40
0 0
5 10G
G H
02
0 0
1.91G
G H
Observational Probes of the Accelerating Expansion
w(z) is close to -1 w(z) crossing the w=-1
w(z) crossing the w=-1
Inconsistent with Minimally Coupled Quintessence
and also with Scalar Tensor Quintessence
if G(t) is increasing with time.
Marginal Consistency of Scalar-Tensor Quintessence withObserved Accelerating Expansion
40
0 0
5 10G
G H
02
0 0
1.97G
G H
Maximal Agreement of Scalar-Tensor Quintessence
with the Full Parameter Range of Observed Acelerating Expansion
G(t) can not increase rapidly with t
(not ‘sharp’ Maximum)
Close to Extremum (Solar System)
G(t) decreases with t (close to a Minimum)
Close to Extremum (Solar System)
SNLS
SNLS
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
)(zw
z
0
02 2
min
2 2min
1 2
: 1 2
1 2
: 1 21 2
1 2
2min
; , ,...,
; , ,...,
; , ,...,
; , ,...,, ,...,
; , ,...,
z
z
obsL i
obsL i
dz
n
dzData d zth
L n
n
Data d z L nn
n
Physical Model H z a a a ansatz
d z a a a
H z a a a
d z a a aa a a
w z a a a
1 2, ,..., na a a
2min 171.7OA
LCP
2min 177.1CDM
0.3m
• All best fit parameterizations cross the phantom divide at z~0.25
• The parametrization with the best χ2 is oscillating
Lazkoz, Nesseris, LP 2005
Trunc. Gold (140 points, z<1) Full Gold (157 points, z<1.7)SNLS (115 points z<1)
SNLS data show no trend for crossing the phantom divide w=-1!
0.24m z
zwwzw
1)( 10
S. Nesseris, L.P. Phys. Rev. D72:123519, 2005
astro-ph/0511040
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
0 0.2m
Gold datasetRiess -et. al. (2004)
SNLS datasetAstier -et. al. (2005)
Other data:CMB, BAO, LSS, Clusters
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
S. Nesseris, L.P. astro-ph/0610092
)(zw Other data:CMB, BAO, LSS, Clusters
z z z
2
300
2 ln1 1( ) 3
( )1 1
DE
DEm
d Hzp z dzw z
z Hz
H
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
Gold datasetRiess -et. al. (2004)
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
SNLS datasetAstier -et. al. (2005)
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
0 0.25 0.5 0.75 1 1.25 1.5 1.75
1.5
1
0.5
0
0.5
1
1.5
Other data:CMB, BAO, LSS, Clusters )(zw
z z z
0 0.3m
z
zwwzw
1)( 10
Minimize:
2 2 2 21 2 1 2 1 2 1 2
22 2 226
1 21 2 1 2 1 2
2 2 2 21
, , , , , ,
; ,, , 1.70 , , 0.469 0.15; , 0.51
0.03 0.017 0.11
CMB m BAO m cl LSS
SCDMgas i gas im m
i gas i
w w w w w w w w
f z w w fR w w A w w g z w w
0 0.2m
11.051.0)(
)('15.01
1
aD
aaD
azg
Eisenstein et. al. 2005Wang, Mukherjee 2006
Allen et. al. 20042dF:Verde et. al.
MNRAS 2002
0 0.2m
0 0.3m
0.2mCMB BAO Clusters LSS
0.3mCMB BAO Clusters LSS
Riess et. al. astro-ph/0611572
Old Gold Filtered Gold+New HST Filtered Gold+New HST+Best of SNLS
S. Nesseris, LP in prep.
Old Gold Filtered Gold+New HST Filtered Gold+New HST+Best of SNLS
Q1: What theories are consistent with range of observed H(z)?
• Cosmological Constant
• Quintessence
• Extended (Scalar–Tensor) Quintessence
• Braneworld models (eg DGP)
• Barotropic fluids (eg Chaplygin Gas)
Q2: What forms of H(z) are inconsistent with each theory? (forbidden sectors)
Q3: What is the overlap of the observationally allowed range of H(z)
with the forbidden sector of each theory?Goal: Address Q2-Q3 for Extended Quintessence
Plausibility Arguments+
Numerical Simulations
Caldwel, Linder 2005
V(Φ)
Φ
V(Φ)
Φ
ThawingThaw Accelerate
FreezingDecelerate Freeze
3dU
Hd
2 28 1
3 2m
GH U
p,
21
2 m mH p F HFF
2 21 13
3 2mH U HFF
dz
d'
Consistency Requirements:
Express Fi in terms of G(t) current time derivatives:
Ignored :1g (Solar System Tests, Pitjeva 2005)
Gannouji, Polarski, Ranquet, Starobinsky astro-ph/0606287
2
0 0zz
Freezing
2
0 0zz Thawing
10 0U z U
2
0 0zz
Freezing
2
0 0zz Thawing
10 0U z U
Lower bound on g2:
Chevallier-Polarski-Linder
Lower bound on g2: Upcoming Solar System Constraints on g2:
5 529 10 10g J. Mueller 2006
Chevallier-Polarski-Linder
2 0 implies decreasing G which helps
boost accleration beyond the w=-1 barrier
g
2Why does 0 shrink the forbidden sector beyond the w=-1 limit?g
SnIa Absolute Luminosity:
Steps of Analysis:
1. Assume G(z) parametrization consistent with Solar System + Nucleosynthesis bounds
2. Consider modified magnitude-redshift relation
3. Minimize χ2
The shift of the contours is not significantcompared to the area of the contours.
40
0 0
10G
G H
02
0 0
1.91G
G H
Observational Probes of the Accelerating Expansion
w(z) is close to -1 w(z) crossing the w=-1
w(z) crossing the w=-1
Inconsistent with Minimally Coupled Quintessence
and also with Scalar Tensor Quintessence
if G(t) is increasing with time.
Consistency of Scalar-Tensor Quintessence
Observed Accelerating Expansion
40
0 0
10G
G H
02
0 0
1.97G
G H
Maximal Agreement of Scalar-Tensor Quintessence
with the full range of observed Acelerating Expansion
G(t) can not increase rapidly with t
(not ‘sharp’ Maximum)
Close to Extremum (Solar System)
G(t) decreases with t (close to a Minimum)
Close to Extremum (Solar System)