Yun Wang
(on behalf of the Euclid Galaxy Clustering SWG)
Euclid Galaxy Clustering SWG Meeting London, March 21, 2012
Cosmic Expansion History from Euclid BAO Measurements
EuclidConsortium
Galaxy Clustering: Baryonic Acoustic Oscillations (BAO) as standard ruler
GalaxiesGalaxiesGalaxiesGalaxies Microwave Microwave backgroundbackgroundMicrowave Microwave backgroundbackground
(WMAP, e.g. Komatsu et al. 2009)Percival et al. (2009,
2010)
Instrument Overall WP Breakdown VG :3
EuclidConsortiumReconstructing power spectra to 1%
Euclid ESA HQ Paris Sept. 12, 2011 Euclid ESA HQ Paris Sept. 12, 2011 Euclid SPR Jan. 19, 2012
Simulated of the Euclid spectro. survey : 100 deg2: effect of redshift errors (red dots). (A. Merson and C. Baugh mocks)
GC redshift-survey: Power spectrum reconstruction with 20% of the Euclid data.(W. Percival)
L1L2PRR Meeting ESTEC 27 May 2011
EuclidConsortiumw(z) from Baryonic Acoustic Oscillations
20% of the Euclid slitless data at z~1
Total effective volume (of Euclid)Veff = 19.7 Gpc3h-3
20% of the Euclid slitless data at z~1
Total effective volume (of Euclid)Veff = 19.7 Gpc3h-3
SDSS LRGs at z~0.35
The largest volume of the Universe currently mapped
Total effective volumeVeff = 0.26 Gpc3h-3
SDSS LRGs at z~0.35
The largest volume of the Universe currently mapped
Total effective volumeVeff = 0.26 Gpc3h-3
EuclidConsortiumThe unique power of Euclid: w(z)
FoM > 400 (e.g. wp~0.016 and wa~0.16)
In this case a cosmological constant is favoured by more than 100:1 over model M: "decisive" statistical evidence in favour of the simplest model, in Bayesian terms
A less precise experiment will not have enough statistical power to favour a cosmological constant over the more complex alternative
Instrument Overall WP Breakdown VG :6
EuclidConsortiumGC-1-1 and WL-1-1 optimal sky coverage ,fixed-length survey
Euclid ESA HQ Paris Sept. 12, 2011 Euclid SPR Jan. 19, 2012
With 15,000 deg2 for for GC and WL: optimisation for a fixed time survey.Most efficient survey, allowsto do WL and GC simulatenously on the same area
Consortium
Instrument Overall WP Breakdown VG :7
EuclidConsortium
Modified Gravity
Dark MatterInitial Conditions
Dark Energy
Parameter mν/eV fNL wp wa FoM
Euclid Primary 0.010 0.027 5.5 0.015 0.150 430
Euclid All 0.009 0.020 2.0 0.013 0.048 1540
Euclid+Planck 0.007 0.019 2.0 0.007 0.035 4020
Current 0.200 0.580 100 0.100 1.500 ~10
Improvement Factor
30 30 50 >10 >40 >400
Planck+Euclid+simulation: FoM L0 requirement met
Euclid ESA HQ Paris Sept. 12, 2011 Euclid ESA HQ Paris Sept. 12, 2011
(WL+GC)
(WL+GC)+CL+ISW
(Euclid All)
Euclid SPR Jan. 19, 2012
Yun Wang, 3/21/2012
DE Forecasting from GCDE Forecasting from GC• Propagate the measurement errors in lnPg(k) into measurement
errors for the parameters pi:
lnPg(k) [Veff(k)]-1/2
=k·r/kr
3
3
)2(2
d)(
)(ln)(lnmax
min k
kkk
effj
g
i
gk
kij V
pP
pP
F
surveyg
g
g
geff
VknP
knP
kPn
kPndV
2
23
1),(
),(
1),()(
),()()(
r
rrk
Yun Wang, 3/21/2012
Two Approaches:Two Approaches:
• “Full P(k)” method:
parametrize P(k) using [H(zi), DA(zi), (zi), G(zi), Pshot
i, nS, mh2, bh2]
• BAO “wiggles only”:
P(k) P(k0.2,|z)[sin(x)/x]·exp[-(ks)1.4-k2 nl2/2]
x=(k2s2+ k//
2s//2)1/2
p1=ln s
-1=ln(DA/s); p2=ln s //=ln(sH);
Yun Wang, 3/21/2012
Assuming Euclid Red Book Baseline:
(deg)2
0.65<z<2.05 e(f,z)
*Updated from Wang et al. (2010)
Figure of Merit vsRedshift Accuracy
Figure of Merit vsRedshift Accuracy
Yun Wang, 3/21/2012
xh(z)=H(z)sxd(z)=DA(z)/s
*Updated from Wang et al. (2010) for Euclid RB baseline*Based on Wang (2012)
Expansion History H(z):BAO vs P(k)
Expansion History H(z):BAO vs P(k)
Yun Wang, 3/21/2012
*Based on Wang (2012)
Constraints on Growth Rate
Constraints on Growth Rate
Yun Wang, 3/21/2012
xh(z)=H(z)sxd(z)=DA(z)/s
pNL=50%
*Updated from Wang et al. (2010) for Euclid RB baseline
*Based on Wang (2012)
DE FoM vs Information Used
DE FoM vs Information Used
Space/Ground Complementarity
Ongoing ground-based surveys (WiggleZ, BOSS) enable better understanding of galaxy clustering, and improved modeling of systematic effects, which benefit Euclid.
Overlaps in redshift range (BOSS, BigBOSS, and Euclid) enable clustering statistics using multiple tracers (LRG, OII3727, and H emitters), which improves DE constraints and the modeling of systematic effects.
Yun Wang, 3/21/2012