1. CLUSTER MASS MEASUREMENTS FROM X-RAY SURVEY DATA
FABIO GASTALDELLO
IASF-INAF MILANO & UC IRVINE
S. ETTORI
OSS. BOLOGNA

2. OUTLINE
CLUSTER SURVEY QUALITY DATA: THE CASE OF THE C1 CLUSTERS IN PACAUD+07
OVERVIEW OF SCALING RELATIONS IN X-RAYS
PROBLEMS: FUNCTIONAL FORM AND ITS EVOLUTION WITH REDSHIFT

3. C1 SAMPLE IN THE 5deg2
WITH THESE NUMBER OF COUNTS SCALING RELATIONS HAVE TO BE USED
Pacaud+07

4. C1 SAMPLE IN THE 5deg2 Pacaud+07
Introduction with NFW and cosmological relevance of the c-M relation with current observational results
Lack of results in the group mass range which spurred the work I’m presenting here.
Method of analysis (bkg subtraction, potential approach to HE equation, care to addressing systematics)
Group results
Cosmological implications of the extended sample ranging from ellipticals to massive clusters (Buote et al. 2006)
Pacaud+07

5. C1 SAMPLE IN THE 5deg2
Pacaud+07

6. X-RAY SCALING LAWS M   DM r2 dr  R3  R T
From hydrostatic equilibrium equation (or isothermal sphere equation):
M   DM r2 dr  R3  R T
Thus, R  T1/2 & M  T3/2
Assuming brehmsstrahlung emission & DM  ngas,
L   ngas2 (T) r2 dr  ngas2 T1/2 R3  fgas2 T2  fgas2 M4/3
Considering that we generally measure these quantities at fixed overdensity  with respect to cr(z) = 3Hz / 8G, these relations scale as (Fz = 1/2 Hz / H0):
Fz M  T3/2
Fz-1 L  T2
Fz-1 L  (Fz M)4/3

7. THE MASS PROXY Yx
Kravtsov+06

8. THE MASS PROXY Yx
Arnaud+07
Vikhlinin+09

9. THE L-M USING L-Yx
SCATTER IN L-M OF %
Maughan 07

10. THE L-M USING L-Yx
Pratt+07

11. A POSSIBLE RECIPE
Use directly L-M with r500 from L-Y and Y-M (see for example XMM-BCS Suhada+12)
Core excised quantities are really the low scatter relations: try Pratt+09 suggestion of using central density as further parameter (if possible, given the uncertainties in the β model fit)
Double check with M-T and/or β model estimate ?
Strategy for follow-up ?

12. A POSSIBLE RECIPE

13. FOLLOW-UP OF XLSSC 029
Maughan+08

14. FOLLOW-UP OF XLSSC 029
Maughan+08

15. PROBLEM: NO SELF-SIMILARITY
Maughan+11

16. PROBLEM: NO SELF-SIMILARITY
Pratt+09
Maughan+11

17. PROBLEM: EVOLUTION WITH z
Pacaud+07
Maughan+11
SELF-SIMILAR EVOLUTION: SLOPE IS z INDIPENDENT AND NORMALIZATION VARY IN PROPORTIONS TO POWER OF E(z). SELECTION BIASES ARE IMPORTANT !!!

18. PROBLEM: EVOLUTION WITH z
Reichert et al. 12

19. PROBLEM: EVOLUTION WITH z
Reichert et al. 12

20. SUMMARY
THE SURVEY QUALITY OF THE DATA OF XXL REASONABLY ALLOWS FOR THE USE OF SCALING RELATIONS WITH L
CENTRAL DENSITY, T AND SPATIAL DISTRIBUTION CAN BE USED
DEPARTURE FROM SELF-SIMILAR POWER LAW EXACTLY AT THE BULK OF THE POPULATION OF XXL ? HOWEVER SUN+11 GOOD AGREEMENT BETWEEN IN THE PRESSURE OF GROUPS AND CLUSTERS
FOR EVOLUTION WITH REDSHIFT THE KNOWLEDGE OF THE SELECTION FUNCTION WILL TEST SELF-SIMILARITY