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The impact of the REFLEX cluster survey in cosmology Ariel Snchez A.Balaguera-Antolinez, H. Boehringer, L. Guzzo, C. Collins, P. Schuecker Vulcano Workshop 2010 Ariel Snchez The impact of REFLEX in cosmology Vulcano 24/05/10 Outline

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SLIDE 1

Ariel Sánchez

A.Balaguera-Antolinez, H. Boehringer,

  • L. Guzzo, C. Collins, P. Schuecker

Vulcano Workshop 2010

The impact of the REFLEX cluster survey in cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 2
  • Introduction: cosmology with clusters of galaxies
  • The REFLEX catalogue
  • The impact of REFLEX on cosmology
  • The near future: REFLEX II

Outline

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 3

Clusters as cosmological probes

  • Clusters are the largest

clearly defined structures

  • Tracers of the large scale

structure of the Universe.

  • n(M,z): depends strongly on

Ωm, wDE and σ8

Introduction

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 4

ΛCDM EdS

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10 Borgani & Guzzo (2001)

Clusters as cosmological probes

Introduction

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SLIDE 5

Clusters as cosmological probes

  • X-ray emission is a good

tracer of gravitational potential

  • Simple scaling relations

between observables (e.g. LX, TX) and mass.

  • Simple selection functions:

flux limited samples

Introduction

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 6

Clusters as cosmological probes

Pratt et al. (2010)

Introduction

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

  • X-ray emission is a good

tracer of gravitational potential

  • Simple scaling relations

between observables (e.g. LX, TX) and mass.

  • Simple selection functions:

flux limited samples

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SLIDE 7
  • REFLEX (ROSAT-ESO Flux Limited X-ray) Cluster Survey.
  • Largest statistically complete X-ray selected sample to date.
  • Combines X-ray data from RASS and ESO follow-up optical
  • bservations.
  • Flux limited sample:
  • Contains 452 clusters with z < 0.45.

The REFLEX catalogue

fX 31012ergs1cm2 0.1 2.4 kev

( )

Introduction

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 8

The REFLEX catalogue

Introduction

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 9

Introduction

The REFLEX catalogue

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 10
  • The luminosity function: observational proxy for n(M)

One-point statistics: cluster abundance

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 11

One-point statistics: the luminosity function

  • REFLEX N(z) (Schuecker et al. 2003)

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 12
  • N(z) contains cosmological information in two ways

Volume element Mass function Mass selection: LX - M and limiting LX

One-point statistics: cluster abundance

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 13

One-point statistics: the luminosity function

  • REFLEX N(z) (Schuecker et al. 2003)
  • Strong degeneracy between Ωm and σ8

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 14

Two-point statistics: the correlation function

  • Two-points statistics are the most used tools for LSS
  • The two-point correlation function is given by

dV

1

dV2 r r

12

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 15

Two-point statistics: the correlation function

  • Two-points statistics are the most used tools for LSS
  • The two-point correlation function is given by

dV

1

dV2 r r

12

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 16

Two-point statistics: the correlation function

  • The REFLEX correlation function (Collins et al. 2000)

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 17

Two-point statistics: the correlation function

  • REFLEX data is

inconsistent with models with Ωm = 1

  • Models with Ωm = 0.3 give

a much better fit to the data.

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 18

Two-point statistics: the power spectrum

  • The power spectrum is the Fourier transform of ξ(r).
  • Clusters are biased tracers of the underlying density field

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 19

Two-point statistics: the power spectrum

  • The REFLEX P(k)

(Schuecker et al. 2001)

  • Excellent agreement

with P(k) of optically selected galaxies.

  • Ruled out strongly non-

linear biasing models. bcg 2.6

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 20

Two-point statistics: the power spectrum

m = 0.3, = 0.7

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 21

Two-point statistics: the power spectrum

  • The combination of P(k) and N(z) improves the constraints
  • The degeneracy between Ωm and σ8 is broken.

m = 0.34 ± 0.030 (stat.) ± 0.08(sys.) 8 = 0.711± 0.035 (stat.) ± 0.14(sys.)

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 22

Two-point statistics: the power spectrum

Schuecker (2005)

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 23

Two-point statistics: the power spectrum

Tegmark & Zaldarriaga (2002), Schuecker (2005)

REFLEX & cosmology

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 24

The present: REFLEX II

  • The enduring value of all-sky surveys: REFLEX II
  • Extension to fX 1.8 1012ergs1cm2

0.1 2.4 kev

( )

REFLEX Il

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 25
  • Same footprint as REFLEX
  • Extension of NORAS (northern hemisphere) ongoing

The present: REFLEX II

REFLEX Il

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 26
  • Several ongoing analysis: Φ(Lx), ξ(r), P(k), ξcg(r), ξ(σ,π)…
  • Goal: obtain robust constraints on cosmological parameters

The present: REFLEX II

REFLEX Il

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 27

Mock catalogues

Mock catalogues

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 28

Mock catalogues

The M - LX relation

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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The two-point correlation function

  • We measured the ξ(r) of the

catalogue and the mocks for different LX cuts.

  • Amplitude increase with

increasing luminosity

  • Good agreement with mock

catalogues

Sánchez et al. (in prep.)

Two-point statistics

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 30

The power spectrum

Balaguera-Antolinez et al. (in prep.)

Two-point statistics

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 31

The power spectrum

  • Flux-limited samples suffer an important problem
  • Larger distances probed by more luminous clusters
  • Introduces a scale dependent distortion in the shape of P(k)

Two-point statistics

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 32
  • Shape of P(k) for flux-limited

samples is distorted.

  • This introduces biases in the
  • btained constraints
  • PVP estimator corrects for this

effect giving good agreement with volume limited samples

The power spectrum

Two-point statistics

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 33

The power spectrum

Two-point statistics

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 34
  • REFLEX was the largest statistically complete X-ray selected

cluster sample.

  • Large impact in cosmology: helped to establish the

concordance cosmological model.

  • This legacy will be continued by the REFLEX II & NORAS II
  • The goal: robust constraints on cosmological parameters with

clusters of galaxies.

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 35

Constraints on cosmological parameters

Sánchez et al. (2009)

  • Best current

constraints:

  • With CMB + shape of

P(k) wDE ~ 20%

  • Full P(k) information + Φ

(LX): wDE ~ 10%

Two-point statistics

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 36

The luminosity function

The data

  • We fitted this Φ(LX) using a Schechter function (solid line):
  • We constructed an extended Schechter function by

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 37

The M - LX relation

  • Assign luminosities to halos according to

with

  • We assume a log-normal scatter of σlog L = 0.114
  • We add a 20% error in LX

Mock catalogues

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 38
  • Fit parameters A, b1 and b2 using a MCMC technique in order

to reproduce the REFLEX II Φ(LX)

Mock catalogues

Mock catalogues

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 39

The power spectrum

Two-point statistics

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 40

The power spectrum

  • To correct for this: weight halos according to their bias

(Percival, Verde & Peacock 2005)

Two-point statistics

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 41
  • These analyses require mock catalogues!
  • We used the L-BASICC II runs:
  • 50 realizations
  • 4483 particles
  • ΛCDM cosmology
  • Lbox=1340 Mpc/h
  • Vtotal = 120 (Gpc/h)3 !!

Image courtesy of R. Angulo

Mock catalogues

Mock catalogues

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 42

The power spectrum

Two-point statistics

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10

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SLIDE 43

Mock catalogues

Mock catalogues

Ariel Sánchez The impact of REFLEX in cosmology Vulcano 24/05/10