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APEX S-Z observations of the XMM-LSS field. Marguerite PIERRE (CEA Saclay) R ü diger KNEISSL (Berkeley). Clusters of galaxies. Center of Abell 2218 viewed by HST z = 0.176. Dark matter: Zwicky 1933. X-ray emission from clusters. MASS fractions: Dark matter : 80% Hot gas : 15%
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APEX S-Z observationsof the XMM-LSS field Marguerite PIERRE (CEA Saclay) Rüdiger KNEISSL (Berkeley)
Clusters of galaxies Center of Abell 2218 viewed by HSTz =0.176 Dark matter: Zwicky 1933
X-ray emission from clusters • MASS fractions: • Dark matter : 80% • Hot gas : 15% • Galaxies : 5% • Theory’s pov A cluster of galaxies = an object with a MASS of ~1014-16 Mo
Cosmology with clusters 0<z<2 Clusters are the most massive entities of the universe Trace the node of the cosmic structure = potential wells (much better than galaxies!) Constraints on cosmology from clusters are complementary to those provided from the CMB and the SN : they do not rely on the same physical phenomena
An example Priors: Wbh2 = 0.0214 +/- 0.002 h = 0.72 +/- 0.08 Rappeti et al 2005
Plan of the talk: close to the first joint X-ray/S-Z survey on large scales • Reminder on the S-Z effect and its cosmological applications • The Apex S-Z instrument • Observations of the XMM-LSS field What will we get? What will we be able to say about cosmology?
The S-Z thermal effect APEX frequencies (from Carlstrom + Bertoldi)
S-Z versus X-ray • SZ : DTCMB ≈ ∫ neTe dl (independent of z – integrated pressure) Integrated SZ (over solid angle) ≈ N<T> /DA2 ≈ M<T> /DA2 • X-ray emissivity : e ≈ n2T1/2 dV Flux (over cluster volume) ≈ ∫edV /DL2 ≈ L/DL2
Cosmological applications of the S-Z effect • Evolution of the number density of clusters + space distribution • Underlying cosmology • Equation of state of the dark energy • S-Z + X-ray • Hubble constant • Angular diameter distance relation out to z~2 • Cluster gas mass fraction => Wm, distance indicator
Caveat ! • In order to constrain cosmology, we must understand how clusters evolve • The detected N(M,z) is not only a result of gravitational physics. • M->T-> Lx (z) , ngaz(z) • The evolution of the physics of the ICM is a key issue: accretion, shocks, feedback, cooling... • for the S-Z and X-ray domains, we must have – or determine – mass-observable relations at any z
The S-Z reciever (Berkeley) 330 elements (TES Bolometers) Commissioning of the full array in spring 2006 Operating l : 2mm (150 GHz), 90 and 220 planned
A few numbers (1) • Apex +tertiary optics built in Berkeley: • FWHM = 1arcmin • XMM • FWHM = 6” (on-axis) • Cluster core radius of 250 kpc • 2.3’ at z =0.1 • 41” at z = 0.5 • 31” at z= 1 • 28” at z= 2
A few numbers (2) • Apex S-Z sensitivity : • 10 mk • XMM point source sensitivity in 10 ks exposure : • 5E-15 erg/s/cm2 in [0.5-2] keV
Current multi-l coverage XMDS & VVDS deep VVDS wide XMM Subaru Deep Survey SPITZER Legacy : SWIRE NOAO Deep Survey Galex X-ray data status: - Received - received - received - Planned and covered by W1 CFHTLS, VLA and Integral
The XMM-LSS/CFHTLS/SWIRE field : an XMM Large Programme XMM pointings : . Done . To be redone . Subaru DS (done) . To be done in 2006-2007 Square = SWIRE 10deg2 field Scuba 2 Legacy
A piece of the XMM-LSS mosaic ~ 1x2 deg2 Where are the clusters ? RASS sources Image by A. Read 10 ks exp. red [0.3-1] keV green [1-2.5] keVblue [2.5-10]keV
Constructing a COMPLETEcluster sample with XMM Suitable for cosmological studies Selection effects controlled a priori : NOT flux limited sample • Clusters span a range of sizes and profiles • Measured flux Emitted flux • groups at 0.3< z < 1
Detection rates Pacaud et al 2006 Core radius (arsec) Countrate
The cluster selection function • Is monitored via extensive simulations • In the following, we a assume a simple flux limit.
CFHTLS Images of D1 clusters C1 z=0.05
CFHTLS Images of D1 clusters C1 z=0.31
CFHTLS Images of D1 clusters C1 z =1.05
Physics of the XMM • For the first time, • the XMM-LSS detects the group (T<2 keV) population out to z=0.5 • We measure the L-T relations of these objects • light on the ICM physics!
The L-T relation ______ L-T at z=0 -------- L-T at z=0.5 (self-similar evolution) 1 4 keV T
A few numbers (3) • Coverage of the 10 deg2 • XMM : ~ 1Ms ~ 12 days • Apex : ~ 2 weeks • Cluster number density • XMM: ~ 15 clusters/deg2 • Apex: 4 clusters/deg2 (> 2-3 E14 Mo) How do the n(z) compare ?
Influence of the low-end of the mass function (X-ray clusters) Pacaud et al, in prep
Influence of the X-ray flux limit Pacaud et al, in prep
Influence of the cosmological parameters on n(z) • Example for X-ray clusters • Similar behaviour for S-Z clusters
Influence of the cluster evolution Pacaud et al, in prep
Influence of the equation of state of the Dark Energy Pacaud et al, in prep
Combining XMM and Apex • Ho / Da comparison vs cosmology • Use the joint data sets to get insights into the evolution of the ICM physics • S-Z integrated pressure along the line of sight • X L-T (z) relation • Add mass information from the weak lensing survey on the CFHTLS data (Refregier et al, in prep) • Calibrate mass-observables relations • Hints on the cosmology