Sunyaev-Zel

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Sunyaev-Zeldovich Signals in Cluster Models
Beth Reid David Spergel Princeton University
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Outline

• SZE surveys Mass-Observable relation
• Thermodynamics of the Intracluster Medium (ICM)
• Clues from X-ray observations
• Results LSZ(M,z) in cluster models
• Implications for cosmological studies and cluster
  physics

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Sunyaev-Zeldovich Effect

• Spectral Distortion of the CMB with magnitude
  fixed by y
• LSZ integrates over the entire cluster
• LSZ is the observable!

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Cosmology with SZE SurveysMeasuring w with
Cluster Number Counts
Figure 1, Mohr, astro-ph/0408484
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Cosmology with SZE SurveysCluster Number Counts

• SZE surveys count clusters

Selection Function - depends on LSZ(M, z), and
possibly gas distribution
Eqn 1, Mohr, astro-ph/0408484
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Motivation
up-scattered clusters

• Understand LSZ(M, z)
• Explore sources of scatter -- will introduce bias

down-scattered clusters
Figure 1 in Lima and Hu (2005), PRD 72, 043006
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Gravitational Heating

• Tgas Tdark
• rac rvir
• Scaling Relations
• LX T2
• T M2/3
• K(r) r1.1

rvir
LX T2.6-2.9
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Thermodynamics of the ICM

• Assume spherical symmetry
• Assume hydrostatic equilibrium
• ICM properties determined by
• Gravitational Potential, ?NFW(r)
• Bounding Accretion Pressure, Pac
• Entropy Profile, K(r)

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X-ray Cluster Observations

• Measure n2?(T), Tspec
• Spherical symmetry
• n(r), T(r)
• Hydrostatic Equilibrium
• Agreement with ?NFW(r) and ?CDM c?

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Perseus Cluster Churazov et al, 2003, ApJ 590 225
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X-ray Cluster Observations 2

• Simple scalings broken
• LX T2.6-2.9
• Non-gravitational processes significant
• Entropy gradients observed

Figure 13b, Pratt and Arnaud, AA 408, 1 (2003)
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Non-gravitational processes Heating

• Supernovae, AGN -- relativistic component?
• Uncertainties encoded in fICM, K(r)

MS0735 (Credit X-ray NASA/CXC/Ohio U./
B.McNamara et al. Radio NRAO/VLA)
Perseus (Credit NASA/CXC/IoA/A.Fabian et al.)
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Non-gravitational processesCooling

• Central cooling times short, little gas below
  Tvir/4
• Cold Cores require central distributed heating
  source (AGN?)
• Uncertainties encoded in fICM, K(r)

Data from Allen et al. 2001, MNRAS 328, 37
Figure 7, astro-ph/0512549 (Peterson and Fabian)
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Cluster Models

• Smooth Accretion Model (Voit et al 2003)
• Phenomenological models vary
• concentration C?
• accretion pressure Pac
• entropy profile K(r)
• ICM mass fraction fICM
• Parameterize K(r) as double power law
• Solve the equation of hydrostatic equilibrium

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Results

• Assumed fICM, Pac consistent with observations of
  hot clusters
• (Vikhlinin et al 2005)

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models
models
models
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• yo and Lx,cut provide similar information
• Our models agree well with the observed LX-yo
  relation

X-ray/SZ data assembled in McCarthy et al. 2003,
ApJ 591, 526.
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Energy Content of the ICM

• Observables LSZ, rsz
• Thermal
• Potential

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ICM Mass Fraction

• Trends observed with mass in nearby clusters in
  both X-ray and SZ

f2500
f500
Figure 21, Vikhlinin et al (2006), ApJ 640, 691
Afshordi, Lin, Sanderson (2005), ApJ 629, 1
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Measuring fICM with kSZ

• Simultaneous tSZ and kSZ detection can
  statistically constrain fICM within same radius

known from ?CDM
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Conclusions

• LSZ fICM M?5/3, largely independent of feedback
  energy injection (SN, AGN, ?)
• SZ redshift evolution determined by
  well-understood DM properties
• fICM is the largest remaining uncertainty can be
  constrained with kSZ
• SZ observations can measure total energy of the
  bound ICM to probe cluster physics
• Scatter c? - 8 K - lt10 simulations - 10-15