1. MASS AND ENTROPY PROFILES OF X-RAY BRIGHT RELAXED GROUPS FABIO GASTALDELLO UC IRVINE & BOLOGNA D. BUOTE P. HUMPHREY L. ZAPPACOSTA J. BULLOCK W. MATHEWS UCSC F. BRIGHENTI BOLOGNA

2. OUTLINE 1.MASS RESULTS AND c-M PLOT FOR X-RAY GROUPS 2.ENTROPY PROFILES 3.AGN FEEDBACK: THE CASE OF AWM4

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

4. c-M RELATION Bullock et al. 2001 c slowly declines as M increases (slope of -0.1) Constant scatter (σ logc ≈ 0.14) the normalization depends sensitively on the cosmological parameters, in particular σ 8 and w (D04,Kuhlen et al. 2005).

5. Concentrations for relaxed halos are larger by 10% compared to the whole population (Jing 2000, Wechsler 2002, Maccio’ 2006). They show also smaller scatter (σ logc ≈ 0.10) Wechsler et al. 2002 Selection Effects

6. A SPECIAL ERA IN X-RAY ASTRONOMY ChandraXMM-Newton 1 arcsec resolution High sensitivity due to high effective area, i.e. more photons

7. NFW a good fit to the mass profile c-M relation is consistent with no variation in c and with the gentle decline with increasing M expected from CDM ( α = - 0.04  0.03, P05). Vikhlinin et al. 2006 Pointecouteau et al. 2005 Clusters X-ray results

8. THE PROJECT Improve significantly the constraints on the c-M relation by analyzing a wider mass range with many more systems, in particular obtaining accurate mass constraints on relaxed systems with 10 12 ≤ M ≤ 10 14 M sun There are very few constraints on groups scale (10 13 ≤ M ≤ 10 14 M sun ), where numerical predictions are more accurate because a large number of halo can be simulated.

9. In Gastaldello et al. 2007 we selected a sample of 16 objects in the 1-3 keV range from the XMM and Chandra archives with the best available data with no obvious disturbance in surface brightness at large scale with a dominant elliptical galaxy at the center with a cool core with a Fe gradient The best we can do to ensure hydrostatic equilibrium and recover mass from X-rays. SELECTION OF THE SAMPLE

11. RESULTS After accounting for the mass of the hot gas, NFW + stars is the best fit model MKW 4 NGC 533

12. RESULTS No detection of stellar mass due to poor sampling in the inner 20 kpc or localized AGN disturbance NGC 5044 Buote et al. 2002

13. RESULTS NFW + stars best fit model We failed to detect stellar mass in all objects, due to poor sampling in the inner 20 kpc or localized AGN disturbance. Stellar M/L in K band for the objects with best available data is 0.57  0.21, in reasonable agreement with SP synthesis models (≈ 1)

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

15. THE X-RAY c-M RELATION Buote et al. 2007 c-M relation for 39 systems ranging in mass from ellipticals to the most massive galaxy clusters (0.06- 20) x 10 14 M sun. A power law fit requires at high significance (6.6σ) that c decreases with increasing M Normalization and scatter consistent with relaxed objects

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

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

18. CAVEATS/FUTURE WORK HE (10-15% from simulations, e.g. Nagai et al. 2006, Rasia et al. 2006). No results yet on the magnitude for the bias on c (if there is one) due to radial dependence of turbulence Selection bias Semi-analytic model prediction of c-M Extend the profiles at large radii (r 500 is possible to reach for groups)

19. MASS CONCLUSIONS The crucial mass regime of groups has provided the crucial evidence of the decrease of c with increasing M c-M relation offers interesting and novel approach to potentially constrain cosmological parameters

20. THE RELEVANCE OF ENTROPY In the widely accepted hierarchical cosmic structure formation predicted by cold dark matter models and in the absence of radiative cooling and supernova/AGN heating, the thermodynamic properties of the hot gas are determined only by gravitational processes, such adiabatic compression during collapse and shock heating by supersonic gas accretion (Kaiser 1986) clusters and group of galaxies should follow similar scaling relations, for example if emission is bremsstrahlung and gas is in hydrostatic equilibrium L  T 2 and if we define as “entropy” K = T/n 2/3, then K  T (so S=k lnK + s 0, it’s also called adiabat because P = K ρ γ ). Entropy reflects more directly the history of heating and cooling of the ICM

21. The L-T relation Mulchaey 2000 It has been clear for many years that the cluster L-T relation does not follow the L  T 2 slope expected for self-similar systems. In practice, L  T 3 for clusters (Edge & Stewart 1991), with possible further steepening to L  T 4 in group regime (Helsdon & Ponman 2000)

22. X-ray surface brightness Ponman, Cannon & Navarro 1999 Overlay of scaled X-ray surface brightness profiles shows that emissivity (hence  gas ) is suppressed and flattened in cool (T<4 keV) systems, relative to hot ones.

23. Entropy in the IGM A larger study, of 66 systems by Ponman et al. (2003), now indicates that there is not a “floor” but a “ramp”, with K(0.1r 200 ) scaling as K  T 2/3, rather than the self- similar scaling of K  T. KTKT

24. PROPOSED EXPLANATIONS 1.EXTERNAL PREHEATING MODELS: the IGM was heated prior to the formation of groups and clusters (e.g. Tozzi & Norman 2001) results in isoentropic cores 2.INTERNAL HEATING MODELS: the gas is heated inside the bound system by supernovae or AGN (e.g. Loewenstein 2000) 3.COOLING MODELS: low entropy gas removed from the system, producing an effect similar to heating (e.g. Voit & Bryan 2001) All three models can reproduce the L-T relation and excess entropy but with some problems: 1 requires too large amount of energy at high redshift 2 requires 100% efficiency from supernovae or fine tuning for AGN 3 overpredicts the amount of stars in groups and clusters More realistic scenarios with both heating and cooling are required (e.g. Borgani et al. 2002)

25. External preheating models with different levels of heating. Large isoentropic cores are produced Internal heating with rising entropy profiles BRIGHENTI & MATHEWS 2001

26. THE BASELINE INTRACLUSTER ENTROPY PROFILE FROM GRAVITATIONAL STRUCTURE FORMATION VOIT ET AL. 2005

27. COMPARISON WITH MASSIVE CLUSTERS AND GRAVITATIONAL SIMULATIONS PRATT ET AL. 2006

28. Entropy in the IGM Higher quality data from XMM and Chandra shows the lack of isentropic cores (e.g. Pratt & Arnaud 2002, Sun et al. 2004). The K  T 2/3 scaling is confirmed, but there is more scatter in entropy for groups. Sun et al 2004

29. ENTROPY PROFILES

30. GASTALDELLO ET AL. 2008, IN PREP.

31. ENTROPY PROFILES GASTALDELLO ET AL. 2008, IN PREP.

32. COMPARISON WITH MASSIVE CLUSTERS AND GRAVITATIONAL SIMULATIONS GASTALDELLO ET AL. 2008, IN PREP.

33. COMPARISON WITH MASSIVE CLUSTERS AND GRAVITATIONAL SIMULATIONS GASTALDELLO ET AL. 2008, IN PREP.

34. GAS FRACTIONS

35. ENTROPY CONCLUSIONS BROKEN POWER LAW ENTROPY PROFILES FOR GROUPS WITH STEEPER INNER SLOPES AND FLATTER OUTER SLOPES SEEM TO POINT TO HIGHER IMPORTANCE OF FEEDBACK PROCESSES WITH RESPECT TO MASSIVE CLUSTERS LOWER GAS FRACTIONS ARE ANOTHER EVIDENCE OF THIS FACT

36. AGN FEEDBACK THE “OLD” MASS SINK PROBLEM IS NOW THE “FEEDBACK PROBLEM” AGN FEEDBACK, PUT ON A FIRMER GROUND BY THE CHANDRA IMAGES, HAS BROADER ASTROPHYSICAL IMPLICATIONS FOR GALAXY FORMATION AND EVOLUTION

37. AGN FEEDBACK Martin Rees “I’VE BEEN ESPECIALLY IMPRESSED BY THE CHANDA X-RAY IMAGES OF GALAXY CLUSTERS. WE SEE HOW GAS IS COOLING DOWN AND HOW THE COOLING IS BEING BALANCED BY TREMENDOUS OUTBURSTS OF JETS AND BUBBLES. THIS IS SOMETHING THAT MOST PEOPLE DIDN’T SUSPECT WAS HAPPENING UNTL THESE IMAGES REEALED IT ”

38. AGN FEEDBACK THE “OLD” MASS SINK PROBLEM IS NOW THE “FEEDBACK PROBLEM” AGN FEEDBACK, PUT ON A FIRMER GROUND BY THE CHANDRA IMAGES, HAS BROADER ASTROPHYSICAL IMPLICATIONS FOR GALAXY FORMATION AND EVOLUTION “SOME LOOSE ENDS REMAIN” (J. BINNEY)

39. AWM4 AND AGN FEEDBACK “In this scenario there is a clear dichotomy between active and radio quiet clusters: one would expect the cluster population to bifurcate into systems with strong temperature gradients and feedback and those without either” Donahue et al. 2005 Gas cools AGN feedback Gas heated AGN stops being fed

40. AWM4 AND AGN FEEDBACK GASTALDELLO ET AL. 2007

41. AWM4 AND AGN FEEDBACK

43. CONCLUSIONS ON AGN FEEDBACK AGN FEEDBACK HAS ALL THE FEATURES OF THE RIGHT SOLUTION BUT WE ARE NOT CLOSE TO A CLEAR UNDERSTANDING AGN FEEDBACK IN GROUPS IS STILL POORLY INVESTIGATED AND THERE ARE SOME PUZZLES, LIKE AWM 4