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The cold component of cluster accretion

The cold component of cluster accretion. Yuval Birnboim Jerusalem 2011. Clusters should be simple!. Abell 1689 Composite: X-ray(Chandra) + Optical (HST). The cooling flow Problem in Cool Core Clusters. No cool (<1keV) gas

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The cold component of cluster accretion

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  1. The cold component of cluster accretion Yuval Birnboim Jerusalem 2011

  2. Clusters should be simple! Abell 1689 Composite: X-ray(Chandra) + Optical (HST)

  3. The cooling flow Problem in Cool Core Clusters • No cool (<1keV) gas • Star formation in brightest central galaxy lower by 10-100 than expected from cooling • BCG smaller by a factor or a few than expected (“failure to thrive”) Allen & Ebeling

  4. Cool Core Cluster properties Leccardi & Molendi 2008 M(BCG) ≤ 1012M SFR≤20 M/yr Lx~1044-1045erg/sec Score~20KeV cm2 Reiprich 2003 Cavagnolo et al. 2009

  5. Overcooling. Mvir=3X1014Mʘ

  6. Immediate suspect: AGNs Artist’s impression for supermassive black hole, NASA/JPL-Caltech M87 – HST image

  7. Criteria for cluster heat source 1) Enough energy 2) Smooth in time (toff<tcool) 3) Smooth in space (<10kpc) 4) No explosions, please

  8. Accretion and Gravitational heating in Clusters Dekel et al. 2009 Dekel & Birnboim 2008

  9. Clusters are not smooth! Courtesy of Volker Springel

  10. Clump physics Heating by baryonic cold (10^4K) clumps • Hydrodynamic drag:

  11. Clump physics Heating by baryonic cold (10^4K) clumps • Hydrodynamic drag • Jeans mass (Bonnor-Ebert) • K-H/R-T instabilities and clump fragmentation • DF • Conduction/evaporation (Gnat et al. 2010) Heating 1gr/cm^3 10-3gr/cm^3

  12. Gravitational heating by clumps Murray & Lin 2004 Dekel & Birnboim 2008

  13. Cold gas in Perseus HVCs in MW Conselice et al. 2001 Mass of structures: 106-108M⊙(Fabian et al. 2008)

  14. Dynamic response Problems with static calculations: • Cold mass is dumped near center • Energy injection is not self regulated • Timescale of clumps: many Gyrs Problems with full 3D hydro: • Resolution Subgrid 1D model: • clump shells interact with gas • At clump destruction – cold mass added in situ

  15. No clump simulation – OvercoolingMvir=3X1014Mʘ

  16. 5% of baryons in clumps of 108M⊙

  17. Convection Stability • Maximal convection (vbubbles=cs) • Mixing length theory (implicit scheme)

  18. 5% of baryons in clumps of 108M⊙Clumps + Convection

  19. 5% of baryons in clumps of 108M⊙Clumps + Convection Birnboim and Dekel. 2011

  20. Summary • Gravitational infall is a powerful engine • Clumps interact with gaseous haloes • and heat them • The inherit instability drives convection

  21. Thank you

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