cosmology with the xmm cluster survey (xcs) martin sahlén, university of sussex with pedro viana...

Cosmology with theCosmology with theXMM Cluster Survey (XCS)XMM Cluster Survey (XCS)

Martin SahlMartin Sahlén, én, University of SussexUniversity of Sussex

withwithPedro Viana (Porto), Andrew Liddle, Kathy Romer (PI)Pedro Viana (Porto), Andrew Liddle, Kathy Romer (PI)

and others (XCS Consortium)and others (XCS Consortium)

COSMO ’07, University of Sussex, 22 August 2007COSMO ’07, University of Sussex, 22 August 2007

M. Sahlén - Cosmology with the XCS M. Sahlén - Cosmology with the XCS

OutlineOutline Why Galaxy Clusters?Why Galaxy Clusters?

From Theory to Predictions:From Theory to Predictions:Simulation and ObservationSimulation and Observation

The XMM Cluster SurveyThe XMM Cluster Survey

ForecastsForecasts

Status and ConclusionsStatus and Conclusions


Why Galaxy Clusters?Why Galaxy Clusters?

Galaxy clusters: largest grav. bound Galaxy clusters: largest grav. bound objects, hot intracluster gas – objects, hot intracluster gas – bremsstrahlung (X-ray)bremsstrahlung (X-ray)

Cluster abundance exponentially sensitive Cluster abundance exponentially sensitive to to σσ88 and and ΩΩMM → good constraining power → good constraining power

Probe structure formation; constraints Probe structure formation; constraints complementary to CMB, SNIa, etc.complementary to CMB, SNIa, etc.

Knop et al. 2003 Allen et al. 2004


Why Galaxy Clusters Again? Why Galaxy Clusters Again?

0.22 0.25 0.28 0.31 0.34

0.75 0.8 0.85 0.9 0.95 1

8

m

8

0.22 0.25 0.28 0.31 0.340.75

0.8

0.850.9

0.95

1

None Linear No NoSelf-similar None No No

Self-similar Linear Yes NoNone None Yes No

L-T evolution L-T & M-T scatterData Fit Data Fit

Self-similar None Yes NoNone Linear Yes No

F iducial

Fiducial

Fiducial


Theoretical ComponentsTheoretical Components

n(M, z) – comoving number density of clustersn(M, z) – comoving number density of clusters M(O, z) – relation between halo mass and direct M(O, z) – relation between halo mass and direct

observableobservable dV/dz – cosmic volume evolutiondV/dz – cosmic volume evolution ffselsel(O,z) – probability of detecting a given cluster (O,z) – probability of detecting a given cluster Uncertainties in observables and relationsUncertainties in observables and relations

dMzMfdz

dVzMnO

dz

dNsel

zM

)),((),()();(

lim

limmin

Dynamics of Cluster ScienceDynamics of Cluster Science

IC’s

Particle physics

Gravita-tional theory

Cosmo-dynamics

Cluster dynamics

Mass function Jenkins et al. 2001

BiasSheth & Tormen 1999

Mass-observable relationsMuanwong et al. 2006

Halo conc.Neto et al. 2007

THEORY SIMULATIONS FITTING FORMULAE

OBSERVATIONS

e.g. XCS

e.g. Virgo Hubble Volume


Mass FunctionMass Function

PPδδ(k) - PS of density contrast; depends on primordial (k) - PS of density contrast; depends on primordial PS, transfer function and perturbation growth PS, transfer function and perturbation growth suppression factorsuppression factor

Primordial spectrum specified, transfer function and Primordial spectrum specified, transfer function and growth factor determined by cosmologygrowth factor determined by cosmology

Here: parameterisation for Here: parameterisation for σσ(R); (R); Viana & Liddle 1996

0

22 )()()(k

dkkPkRWR

dMdM

zMd

zMM

zFdMzMn m ),(

),(

)()(),(

8.31 61.0lnexp315.0)( JF

)(

18 Mpc8)(

R

h

RR

Jenkins mass function; Jenkins mass function; Jenkins et al. 2001


Mass-Observable/Scaling Mass-Observable/Scaling RelationsRelations

Luminosity-TemperatureLuminosity-Temperature

Mass-TemperatureMass-Temperature

Evolution (Evolution (γγ, , δδ, , ηη, , νν)) Self-similar Self-similar γγ = 1/2, = 1/2, ηη = 1/3 = 1/3

Scatter (Scatter (σσlogLlogL, , σσlogTlogT))

Self-calibration and follow-upSelf-calibration and follow-up

)1(*)(*)(

)()(*),(),(

2

2

zzEz

zEzzTLzTL

vir

vir

),0()1()()(log),(log log223/2

1010 Tvirvir NzzzEhAMzMT

e.g. Levine et al. 2002, Lima & Hu 2004, 2005, Majumdar & Mohr 2004

),0(log*),(log log1010 LNTzTL


XMM Cluster Survey (XCS)XMM Cluster Survey (XCS)

Mining XMM-Newton imagesMining XMM-Newton images X-ray temperature, flux, redshiftX-ray temperature, flux, redshift

2 keV < T < 8 keV, z2 keV < T < 8 keV, zmaxmax = 1.45 = 1.45

500 500 □□˚̊ Important ‘pathfinder’ Important ‘pathfinder’

survey for e.g. SPT,survey for e.g. SPT,

E-ROSITA, and DESE-ROSITA, and DES

(XCS collaboration)(XCS collaboration) http://xcs-home.orghttp://xcs-home.org


Selection FunctionSelection Function

Calculated using cluster detection pipeline Calculated using cluster detection pipeline with mock clusters - numerically very with mock clusters - numerically very intensive to compute (months)intensive to compute (months)

Dependencies include:Dependencies include: Halo modelHalo model X-ray spectrumX-ray spectrum Detector characteristicsDetector characteristics CosmologyCosmology


Mock cluster added to image

Detecting Mock ClustersDetecting Mock Clusters

Original XMM-Newton image Original source detectionMock source detection


From Theory to PredictionsFrom Theory to Predictions N-body/hydrodynamic simulations - full non-linear N-body/hydrodynamic simulations - full non-linear

treatment, necessary!treatment, necessary!

Mass function, mass-observable relations, etc. Mass function, mass-observable relations, etc. calibrated to simulations/observationscalibrated to simulations/observations

Selection function: simulations using the Selection function: simulations using the detection pipelinedetection pipeline

Used along with cosmology to make predictionsUsed along with cosmology to make predictions

ttttt

tttseltttttt

z

z

T

T

dzdTdLdMdz

dVzTLfzMnzTLMzTLMpzTn

dTdzzTnTTzzN

),,(),(,,,|,,,),(

),(),,,(2

1

2

1

2121


Expected Number CountsExpected Number CountsFull XCS;Full XCS;ΩΩM M = 0.3= 0.3ΩΩΛΛ = 0.7 = 0.7σσ8 8 = 0.8= 0.8

Self-sim M-TSelf-sim M-T

Scatter:Scatter:σσlogL logL = 0.3= 0.3σσlogT logT = 0.1= 0.1

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

10

20

30

40

50

60

70

z

Mea

n nu

mbe

r of

clu

ster

s in

bin

,

z =

0.0

5

M-T & L-T scatter, self-similar L-TM-T & L-T scatter, constant L-T

No scatter, self-similar L-TNo scatter, constant L-T


Expected Constraints, Full XCSExpected Constraints, Full XCSFiducialFiducial::ΩΩM M = 0.3= 0.3ΩΩΛΛ = 0.7 = 0.7σσ8 8 = 0.8= 0.8Self-similar M-TSelf-similar M-TNo scatterNo scatter

500 500 □□˚̊2 keV < T < 8 keV2 keV < T < 8 keV0.1 < z < 10.1 < z < 1Flat universeFlat universe

0.28 0.29 0.3 0.31

0.78 0.8 0.82 0.84

8

m

8

0.29 0.3 0.31

0.78

0.8

0.82

No L-T evolution

Self-similar/linear L-Tevolution

F iducial


Systematic BiasesSystematic Biases

0.22 0.25 0.28 0.31 0.34

0.75 0.8 0.85 0.9 0.95 1

8

m

8

0.22 0.25 0.28 0.31 0.340.75

0.8

0.850.9

0.95

1

None Linear No NoSelf-similar None No No

Self-similar Linear Yes NoNone None Yes No

L-T evolution L-T & M-T scatterData Fit Data Fit

Self-similar None Yes NoNone Linear Yes No

F iducial

Fiducial

Fiducial


StatusStatus XCS DR1 XCS DR1

168 168 □□˚̊

Exp. ~50-250 clusters with >500 photons and T > 2 keVExp. ~50-250 clusters with >500 photons and T > 2 keV

166 candidates, 119 confirmed with redshift, BUT clusters 166 candidates, 119 confirmed with redshift, BUT clusters with T < 2 keV not excluded yetwith T < 2 keV not excluded yet

Results expected late 2008Results expected late 2008

Full XCSFull XCS 500 500 □□˚̊

Exp. ~200-700 clusters with >500 photons and T > 2 keVExp. ~200-700 clusters with >500 photons and T > 2 keV

Results expected 2010Results expected 2010


ConclusionsConclusions

Cluster cosmology can be modeled Cluster cosmology can be modeled using N-body/hydrodynamic using N-body/hydrodynamic simulation results tuned to simulation results tuned to observationsobservations

A comprehensive MCMC forecasting A comprehensive MCMC forecasting and data analysis code has been and data analysis code has been developeddeveloped


ConclusionsConclusions

XCS DR1 (2008): XCS DR1 (2008): σσ88 to 15%, to 15%, ΩΩMM to 25% to 25% (~WMAP3)(~WMAP3)

Full XCS (2010): Full XCS (2010): σσ88 and and ΩΩMM to 5% to 5%

Knowledge of L-T scatter and evolution Knowledge of L-T scatter and evolution necessary (self-calibration/follow-up)necessary (self-calibration/follow-up)

XCS is a key step for cluster surveysXCS is a key step for cluster surveys


Ongoing WorkOngoing Work

Self-calibrationSelf-calibration

Temperature & redshift errorsTemperature & redshift errors

Future/reference surveysFuture/reference surveys

cosmology with the xmm cluster survey (xcs) martin sahlén, university of sussex with pedro viana...

Documents

sahln cosmology

xcs consortiumcosmo

xcs outlinewhy galaxy

xcs theoretical componentsnm

xcs systematic biasesm

jenkins mass function

halo mass

transfer function