MASS AND ENTROPY PROFILES OF X-RAY BRIGHT RELAXED GROUPS

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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
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OUTLINE

• MASS RESULTS AND c-M PLOT FOR X-RAY GROUPS
• ENTROPY PROFILES
• FOCUS ON SOME PARTICULAR OBJECTS

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

• c slowly declines as M increases (slope of -0.1)
• Constant scatter (slogc 0.14)
• the normalization depends sensitively on the
  cosmological parameters, in particular s8 and w
  (D04,Kuhlen et al. 2005).

Bullock et al. 2001
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Selection Effects
Wechsler et al. 2002
Concentrations for relaxed halos are larger by
10 compared to the whole population (Jing 2000,
Wechsler 2002, Maccio 2006). They show also
smaller scatter (slogc 0.10)
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A SPECIAL ERA IN X-RAY ASTRONOMY

• High sensitivity due to high effective area, i.e.
  more photons

• 1 arcsec resolution

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Clusters X-ray results
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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
  1012 M 1014 Msun
• There are very few constraints on groups scale
  (1013 M 1014 Msun) , where numerical
  predictions are more accurate because a large
  number of halo can be simulated.

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SELECTION OF THE SAMPLE

• 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.

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RESULTS

• After accounting for the mass of the hot gas, NFW
  stars is the best fit model

MKW 4
NGC 533
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RESULTS

• No detection of stellar mass due to poor sampling
  in the inner 20 kpc or localized AGN disturbance

Buote et al. 2002
NGC 5044
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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)
• Adopting more complicated models, like
  introducing AC or N04 did not improve the fits.
  AC produces too low stellar mass-to-light ratios

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c-M relation for groups
We obtain a slope a-0.226?0.076, c decreases
with M at the 3s level
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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 1014 Msun.
• A power law fit requires at high significance
  (6.6s) that c decreases with increasing M
• Normalization and scatter consistent with relaxed
  objects

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THE X-RAY c-M RELATION
WMAP 1 yr Spergel et al. 2003
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THE X-RAY c-M RELATION
WMAP 3yr Spergel et al. 2006
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CLUSTERS PREFER HIGH s8
Evrard et al. 2007
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CLUSTERS PREFER HIGH s8
Evrard et al. 2007
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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
• Gas physics and AC (problems also with rotation
  curves of spirals Kassim et al. 2006, Gnedin et
  al. 2006 but also positive claims M31 mass model
  of Seigar et al. 2007)
• Extend the profiles at large radii (r500 is
  possible to reach for groups)

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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
• See constraints on the c-z relation (poster by L.
  Zappacosta)

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ENTROPY PROFILES
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ENTROPY PROFILES
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ENTROPY PROFILES
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THE BASELINE INTRACLUSTER ENTROPY PROFILE FROM
GRAVITATIONAL STRUCTURE FORMATION
VOIT ET AL. 2005
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COMPARISON WITH MASSIVE CLUSTERS AND
GRAVITATIONAL SIMULATIONS
PRATT ET AL. 2006
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COMPARISON WITH MASSIVE CLUSTERS AND
GRAVITATIONAL SIMULATIONS
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COMPARISON WITH MASSIVE CLUSTERS AND
GRAVITATIONAL SIMULATIONS
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ENTROPY PROFILES FOR AGN HEATING
VOIT ET AL. 2006
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ENTROPY PROFILES
NGC 4325 AGN DISTURBANCE RUSSELL ET AL. 2007
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ENTROPY PROFILES
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RGH80
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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
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AWM4 AND AGN FEEDBACK
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AWM4 AND AGN FEEDBACK
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ENTROPY CONCLUSIONS
BROKEN POWER LAW ENTROPY PROFILES FOR GROUPS WITH
STEEPER INNER SLOPES AND FLATTER OUTER SLOPES
SEEM TO POINT TO HIGHER IMPORTANCE OF LOCAL AGN
HEATING INTERPLAY BETWEEN AGN AND MERGINGS THE
PUZZLE AWM4 (MORE DATA RADIO, POSTER BY S.
GIACINTUCCI, CHANDRA !)