cosmological constraints from estimates of m gas -m tot -c in x-ray luminous clusters
DESCRIPTION
Cosmological constraints from estimates of M gas -M tot -c in X-ray luminous clusters. S. Ettori (INAF/OA Bologna) with F. Gastaldello, M. Meneghetti, I. Balestra, S. Borgani, S. Molendi, P. Tozzi et al. Potsdam, September 23, 2009: cosmological constraints from X-ray luminous clusters. - PowerPoint PPT PresentationTRANSCRIPT
Cosmological constraints from estimates of Mgas-
Mtot-c in X-ray luminous
clustersS. Ettori (INAF/OA Bologna)
with F. Gastaldello, M. Meneghetti,
I. Balestra, S. Borgani, S. Molendi, P. Tozzi et al.
Potsdam, September 23, 2009: cosmological constraints from X-ray luminous clusters
Outline
• How good are the estimates of Mgas , Mtot , c: results from hydrodynamical simulations
• Clusters as cosmological probes: uncertainties are in the outskirts
• Concentration – Mtot relation & fgas: a new approach to constrain σ8 & Ωm
X-ray vs lensing mass: simulations
Hydrodynamical simulations of 3 massive clusters(0.7-1.1e15 Msun).
Analyzed after convolution with X-ray (XMAS) andlensing (SkyLens)exposures.
Meneghetti et al. 09 subm
X-ray vs lensing mass: simulations
Meneghetti et al. 09 subm
XMAS SkyLens
X-ray total & gas mass
whatever the projection/method is Mgas is recovered within few (~5) %
MX vs Mtrue: -12 (rms: 5) %
ML vs Mtrue: 2 (rms: 16) %
Mtot
Mgas
X-ray vs lensing mass: simulations
Considering only the projection of g1 & g72:
• c from X-ray analysis: biased low by 10-20 (rms 13) %• c from W only: +88 (rms 50) %, S only +12 (38) %• c from W+S lensing: good agreement (rms 14) %
Concentration from fitting a NFW profile
Gas mass fraction
We combine a dynamical and a geometrical method
(see also Allen et al, Blanchard et al., Ettori et al, Mohr et al) :
• baryonic content of galaxy clusters is representative of the cosmic baryon fraction Ωb / Ωm (White et al. 93)
• fgas is assumed constant in cosmic time in very massive systems (Sasaki 96, Pen 97)
To constrain the cosmological model
Ωm +Ω +Ωk =1
X-ray total massTotal mass from X-ray is determined by assuming
1. spherical symmetry, 2. hydrostatic equilibrium
n~ -2/-2.4 T~ 0/-0.8
€
M tot (< r)∝ r × Tgas(r) × (−α n −α T )
€
M tot < r( ) = −kTgas(r) r
Gμmp
∂ ln ngas∂ ln r
+∂ ln Tgas∂ ln r
⎛
⎝ ⎜
⎞
⎠ ⎟
An example: RXJ1252, z=1.235
An example: RXJ1252, z=1.237
We fit a single absorbed MEKAL to measure Te(Rosati et al. 04).
The deprojected Sb provides ne that is then fitted with a functional form.
NOTE: 850 cts <35”, 1220 cts <59” (rc~10”, 250 cts)
Systematics on Ωm- Ω -w assuming T(r) as observed in local systems (e.g. Vikhlinin et
al. 06)
For details see Ettori et al. 09, arXiv:0904.2740
WMAP-5
Bkg: dominant in GCs Bkg: dominant in GCs outskirtsoutskirts
Simulation for 3keV cluster @ R200Simulation for 3keV cluster @ R200
Gal foreground
Ins. background
Residual CXB
Source
ICM at R200: Observed clusters
A1795 with Suzaku by M.Bautz et al. : T ~ r -0.9, M500 ~20-30% < expected
XMM (Leccardi & Molendi 08)
Study of Sb at r >0.7 R200 in a sample of high-z (z>0.3) objects with CXO (Ettori & Balestra 09)fit of the derivative of ln(Sb)/ln( r):
at 0.7 R200: -3.9 ± 0.7, at R200: -4.3 ± 0.9
On the Temperature profile
Chandra
XMM
EDGE 1Msec
arXiv:0707.4103
On the Temperature profile
Chandra
XMM
WFXT 50ksec
The c-Mtot relation
We (Ettori et al. 09 in prep) recover Mgas & Mtot from 44 X-ray luminous galaxy clusters observed with XMM-Newton in the z-range 0.1-0.3 (from
Leccardi & Molendi 2008) to constrain (σ8, Ωm).
We use 2 independent methods & check several systematics on Mtot
The c-Mtot relation: σ8-Ωm
Dotted lines: Eke et al. (01)for a given ΛCDM at z=0 (from top to bottom: σ8=0.9 and 0.7).
Shaded regions: Maccio’ et al. (08, see Bullock et al. 01) for WMAP-1, 5 and 3 years (from the top to the bottom, respectively).
Dashed lines (thin: z=0.1, thick: z=0.3) indicate the best-fit range at 1σ in a WMAP-5 yrs cosmology from Duffy et al. (08)
z<0.15 0.15<z<0.25 z>0.25
The c-Mtot relation: σ8-Ωm
• We constrain (σ8, Ωm) by comparing our estimates of (c200, M200) to the predictions tuned from CDM simulations (black contours)
• We consider both systematics (e.g. different T profiles; fitted ngas; no-limits on
rs; two methods: ~10%) in our measurements & scatter from numerical predictions (~20%, e.g. Neto et al. 07)
• We add constraints from fbar (red contours).
Eke et al. 01
σ8 = 0.94±0.25Ωm=0.25+0.2
-0.1
σ8 = 0.86±0.06Ωm=0.28±0.01
CONCLUSIONS on c–Mtot-fgas• X-ray techniques provide Mgas & Mtot with a good control of both statistical & systematic uncertainties
• A selection of relaxed, massive objects over a large z-range can constrain some cosmological parameters (σ8, Ωm, ΩΛ) through estimates in the c-Mtot-fgas plane
• CAVEAT: N-body community ’d realize an adequate sets of cosmological simulations over a large box to properly predict the expected concentration associated to the massive (>1014 Msun) DM halos as function of (σ8, Ωm; z)