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THE X-RAY C-M RELATION

THE X-RAY C-M RELATION. FABIO GASTALDELLO INAF-IASF MILANO, UCI D. BUOTE, S. ETTORI, P. HUMPHREY, L. ZAPPACOSTA, A. LECCARDI, S. MOLENDI, M. ROSSETTI, J. BULLOCK, M. MENEGHETTI, W. MATHEWS, F. BRIGHENTI. INTRODUCTION: c-M AS COSMOLOGICAL TOOL c-M RELATION FOR THE LOCAL SAMPLE

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THE X-RAY C-M RELATION

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  1. THE X-RAY C-M RELATION FABIO GASTALDELLO INAF-IASF MILANO, UCI D. BUOTE, S. ETTORI, P. HUMPHREY, L. ZAPPACOSTA, A. LECCARDI, S. MOLENDI, M. ROSSETTI, J. BULLOCK, M. MENEGHETTI, W. MATHEWS, F. BRIGHENTI

  2. INTRODUCTION: c-M AS COSMOLOGICAL TOOL • c-M RELATION FOR THE LOCAL SAMPLE • c-M FOR THE SAMPLE OF 44 CLUSTERS AT z=0.1-0.3 • CONCLUSIONS OUTLINE

  3. DM DENSITY PROFILE The concentration parameter c do not depend strongly on the innermost data points, r < 0.05 rvir (Bullock et al. 2001, B01; Dolag et al. 2004, D04). Navarro et al. 2004

  4. c slowly declines as M increases (slope of -0.1) • Constant scatter (σlogc ≈ 0.14) • the normalization depends sensitively on the cosmological parameters, in particular σ8 and w (D04;Kuhlen et al. 2005; Macciò et al. 2008,M08). c-M RELATION Bullock et al. 2001

  5. c-M RELATION Macciò et al. 2008

  6. X-RAY MASS DETERMINATION • Spectra averaged within circular annuli • Normalization / shape of spectrum gives gas density / temperature

  7. X-RAY MASS DETERMINATION A) Deproject with no need to assume parametrized quantities for gas quantities but smoothing required to obtain a physical mass profile (smoothed inversion) B) Forward-fitting: fit gas density and temperature simultaneously assuming only parameterizations for density (or T or entropy) and mass Buote & Humphrey 11

  8. STARS GAS DM • After accounting for the mass of the hot gas, NFW (+ stars) is the best fit model RESULTS MKW 4 NGC 533

  9. THE LOCAL X-RAY c-M RELATION • Buote, Gastaldello et al. 2007: c-M relation for 39 systems ranging in mass from ellipticals to the most massive galaxy clusters (0.06-20) x 1014 Msun. • A power law fit requires at high significance (6.6σ) that c decreases with increasing M (slope -0.172 ± 0.026) • Normalization and scatter consistent with relaxed objects

  10. THE LOCAL X-RAY c-M RELATION WMAP 1 yr Spergel et al. 2003

  11. THE LOCAL X-RAY c-M RELATION WMAP 3yr Spergel et al. 2006

  12. c-M relation for groups We obtain a slope α=-0.2260.076, c decreases with M at the 3σ level

  13. In Ettori, Gastaldello et al. (2010) we used the sample from Leccardi & Molendi (2008), all hot clusters (kT > 3.3 keV) in the range 0.1 < z < 0.3, with detailed temperature profiles secured by performing accurate background modelling • Even though clusters showing evidence of recent and strong interactions were excluded, we have not only regular and relaxed clusters in the sample. They are characterized by the entropy ratios, following Leccardi et al. (2010), which are closely related to the dynamical disturbance THE SAMPLE @ z = 0.1 – 0.3 A 2204 LEC A 1763 HEC

  14. c-M @ z = 0.1 – 0.3

  15. c-M @ z = 0.1 – 0.3 Slope steeper than predicted by simulations, it can not be constrained in the narrow mass range (all -0.50 ± 0.07, LEC -0.28 ± 0.15). Normalization in agreement. Constraints improve when considering only clusters with rs within the data and only LEC clusters. Concentration biased high in disturbed systems (e.g., Lau et al. 2009).

  16. COSMOLOGICAL CONSTRAINTS

  17. HYDROSTATIC EQUILIBRIUM • SELECTION EFFECTS • RADIAL RANGE OF DATA TO OBTAIN MASS PROFILE • THEORETICAL/SIMULATION PREDICTION • ADIABATIC CONTRACTION OPEN ISSUES

  18. BIAS IN HE DERIVED c Lau et al. (2009) TURBULENT PRESSURE RISING W/ RADIUS AND MORE IMPORTANT IN DISTURBED OBJECTS. SEE RASIA ET AL., MENEGHETTI ET AL.

  19. SELECTION EFFECTS De Boni et al. 2013 Wechsler et al. 2002 WHAT ARE WE REALLY SELECTING WHEN WE SELECT “RELAXED” OBJECTS ?

  20. RADIAL RANGE OF DATA RXJ 1159 Humphrey et al. (2012)

  21. c-M relation as determined from X-rays has provided independent evidence of hierarchical structure formation, in particular when fitted over a wide range of masses • c-M relation offers interesting and novel approach to potentially constrain cosmological parameters. Selection effects, HE, radial range of the data, response of DM to baryons (adiabatic contraction) and semi-analytic/ N-body simulations are open issues which have to be better characterized and improved. SUMMARY & CONCLUSIONS

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