Cosmography With Galaxy Clusters: Shedding Light on Dark ... Tuesday/Soares-Santos.pdf ·...

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Cosmography With Galaxy Clusters: Shedding Light on Dark Energy Marcelle Soares-Santos – IAG/USP R. R. de Carvalho – INPE/MCT F. La Barbera – INAF/OAC S. Dodelson – Fermilab J. E. Horvath – IAG/USP

Transcript of Cosmography With Galaxy Clusters: Shedding Light on Dark ... Tuesday/Soares-Santos.pdf ·...

Page 1: Cosmography With Galaxy Clusters: Shedding Light on Dark ... Tuesday/Soares-Santos.pdf · Cosmography With Galaxy Clusters: Shedding Light on Dark Energy Marcelle Soares-Santos –IAG/USP

Cosmography With Galaxy

Clusters: Shedding Light on

Dark Energy

Marcelle Soares-Santos – IAG/USP

R. R. de Carvalho – INPE/MCT

F. La Barbera – INAF/OAC

S. Dodelson – Fermilab

J. E. Horvath – IAG/USP

Page 2: Cosmography With Galaxy Clusters: Shedding Light on Dark ... Tuesday/Soares-Santos.pdf · Cosmography With Galaxy Clusters: Shedding Light on Dark Energy Marcelle Soares-Santos –IAG/USP

DE's

equation of

state

p(ρ) = ?

Accelerated Expansion and Dark Energy

Einstein

equations

Gµν = 8πG Tµν

1st Friedmann

equation

ä = -4πG/3 (ρ+3p)a

2nd Friedmann

equationȧ² = 8πG/3 ρ a² - k

ä > 0 implies

p < - ρ/3

benchmark

model

Ωm= 0.3

ΩΛ= 0.7

p = - ρ

SNe experimentsSpergel et al. 1998

Riess et al. 1998

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mass function

f(M) = dn/dM

Press-Schechter 1974

Sheth-Tormen 1999

Jenkins et al. 2001

effect of w >> difference between PS, ST, J

Munshi et al. 2005

cluster

abundance

dN/dzdΩ

p = w ρ

w<0

dN = n dV

comoving

volume

element

Cluster Abundance Probes

DE's Equation of State

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Kilo-Degree Survey

KIDS/Vesuvio@VST

INAF/OAC

Leiden Observatory

VST Exploration of SUperclusters, Voids and Intermediate Objects

sky area:

1500 sq deg

bands:

u' g' r' i' z'

depth:

r' ~ 24.4

i' ~ 23.4

(z ~ 1.5)

VLT Survey Telescope

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La Barbera et al. 2005

2DPHOT

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z = 0.5 z = 0.9 z = 1.2 z = 1.5

M = 1015 solar masses

Voronoi Tesselation Method (Ramella et al. 2001)

Cluster Identification With 2DPHOT

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Cluster Completeness Function

de Carvalho et al. 2007

Page 8: Cosmography With Galaxy Clusters: Shedding Light on Dark ... Tuesday/Soares-Santos.pdf · Cosmography With Galaxy Clusters: Shedding Light on Dark Energy Marcelle Soares-Santos –IAG/USP

Number of Clusters per sq deg

de Carvalho et al. 2007

KIDS/Vesuvio

1500 sq deg

z~1.5

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Constraints on w: forecasts

fiducial model: ΛCDM

fixed parameters:

σ8= 1.0

h = 0.72

Ωx= 1 - Ω

m

ST mass function

redshift range:

0.5 ≤ z ≤ 1.5

mass threshold:

1014.5 solar masses

Fisher Matrix

Monte Carlo Simulation

Soares-Santos et al. 2007

2%

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cluster abundance is a powerful tool to constrain theories of DE

applying 2DPHOT on simulated images we find that KIDS would allow measurements of galaxy clusters more massive than 1014.5h−1solar masses up to z~1.5, with a completeness of 100%

Summary & Conclusions

cluster abundance obtained from KIDS data using 2DPHOTwill establish strong constraints on DE's equation of state: -0.98 ≤ w≤ -1.02, with 1σ confidence level

KIDS/VESUVIO, covers 1500 sq deg on the sky with

depth up to z~1.5

constraints on cosmological parameters are predicted from

FM and MC simulations