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CLUSTER MASS MEASUREMENTS FROM X-RAY SURVEY DATA. FABIO GASTALDELLO IASF-INAF MILANO & UC IRVINE S. ETTORI OSS. BOLOGNA. 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.
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CLUSTER MASS MEASUREMENTS FROM X-RAY SURVEY DATA FABIO GASTALDELLO IASF-INAF MILANO & UC IRVINE S. ETTORI OSS. BOLOGNA
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 OUTLINE
C1 SAMPLE IN THE 5deg2 • WITH THESE NUMBER OF COUNTS SCALING RELATIONS HAVE TO BE USED Pacaud+07
C1 SAMPLE IN THE 5deg2 Pacaud+07
C1 SAMPLE IN THE 5deg2 Pacaud+07
From hydrostatic equilibrium equation (or isothermal sphere equation): • M DM r2dr R3 R T • Thus, R T1/2 & M T3/2 • Assuming brehmsstrahlung emission & DM ngas, • L ngas2 (T) r2dr 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 / 8G, these relations scale as (Fz = 1/2 Hz / H0): • Fz M T3/2 • Fz-1 L T2 • Fz-1 L (Fz M)4/3 X-RAY SCALING LAWS
THE MASS PROXY Yx Kravtsov+06
THE MASS PROXY Yx Arnaud+07 Vikhlinin+09
THE L-M USING L-Yx SCATTER IN L-M OF 17-21 % Maughan 07
THE L-M USING L-Yx Pratt+07
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 ? A POSSIBLE RECIPE
FOLLOW-UP OF XLSSC 029 Maughan+08
FOLLOW-UP OF XLSSC 029 Maughan+08
PROBLEM: NO SELF-SIMILARITY Maughan+11
PROBLEM: NO SELF-SIMILARITY Maughan+11 Pratt+09
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 !!!
Reichert et al. 12 PROBLEM: EVOLUTION WITH z
Reichert et al. 12 PROBLEM: EVOLUTION WITH z
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 SUMMARY