CLUSTER MASS MEASUREMENTS FROM X-RAY SURVEY DATA
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Transcript of CLUSTER MASS MEASUREMENTS FROM X-RAY SURVEY DATA
CLUSTER MASS CLUSTER MASS MEASUREMENTS FROM X-RAY MEASUREMENTS FROM X-RAY
SURVEY DATASURVEY 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 OUTLINE
C1 SAMPLE IN THE 5degC1 SAMPLE IN THE 5deg22
WITH THESE NUMBER OF COUNTS SCALING RELATIONS HAVE TO BE USED
Pacaud+07
C1 SAMPLE IN THE 5degC1 SAMPLE IN THE 5deg22
Pacaud+07
C1 SAMPLE IN THE 5degC1 SAMPLE IN THE 5deg22
Pacaud+07
X-RAY SCALING LAWS X-RAY SCALING LAWS 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 ngas
2 (T) r2 dr ngas2 T1/2 R3
fgas2 T2 fgas
2 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
THE MASS PROXY Yx THE MASS PROXY Yx
Kravtsov+06
THE MASS PROXY Yx THE MASS PROXY Yx
Arnaud+07 Vikhlinin+09
THE L-M USING L-Yx THE L-M USING L-Yx
Maughan 07SCATTER IN L-M OF 17-21 %
THE L-M USING L-Yx THE L-M USING L-Yx
Pratt+07
A POSSIBLE RECIPEA 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 ?
A POSSIBLE RECIPEA POSSIBLE RECIPE
FOLLOW-UP OF XLSSC 029FOLLOW-UP OF XLSSC 029
Maughan+08
FOLLOW-UP OF XLSSC 029FOLLOW-UP OF XLSSC 029
Maughan+08
PROBLEM: NO SELF-SIMILARITYPROBLEM: NO SELF-SIMILARITY
Maughan+11
PROBLEM: NO SELF-SIMILARITYPROBLEM: NO SELF-SIMILARITY
Maughan+11
Pratt+09
PROBLEM: EVOLUTION WITH zPROBLEM: EVOLUTION WITH z
SELF-SIMILAR EVOLUTION: SLOPE IS z INDIPENDENT AND NORMALIZATION VARY IN PROPORTIONS TO POWER OF E(z). SELECTION BIASES ARE IMPORTANT !!!
Pacaud+07
Maughan+11
PROBLEM: EVOLUTION WITH zPROBLEM: EVOLUTION WITH zReichert et al. 12
PROBLEM: EVOLUTION WITH zPROBLEM: EVOLUTION WITH zReichert et al. 12
• 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 SUMMARY