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Frenk, Bauch Cole, Lacey

Wang 2000; Chandra obs of NGC4632. Frenk, Bauch Cole, Lacey. Hydrostatic Equilirium of Gas in DM potential wells. Radiative Cooling: I Collisional Excitation. v. T ~ 10 5 - 10 8 K. j. g. i. v. hv=E ij. Condition: En. of Elettrons E ≈ KT > D E lu. Collision rate.

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Frenk, Bauch Cole, Lacey

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  1. Wang 2000; Chandra obs of NGC4632. Frenk, Bauch Cole, Lacey

  2. Hydrostatic Equilirium of Gas in DM potential wells

  3. Radiative Cooling: I Collisional Excitation v T ~ 105 - 108 K j g i v hv=Eij Condition: En. of Elettrons E ≈ KT > D Elu Collision rate Number of electrons above the threshold s 2 ~ 1/v 2 ( Coulomb focussing) x Quantum factors

  4. Log L exp(-DE/T) T1/2 Log T

  5. Radiative Cooling: II Free-Free Emission At temperatures T>106 K (DM haloes wth M>1013 Mʘ) the gas is completely ionized. The emission is due to bremsstrahlung from free electrons Log L T1/2 6 Log T

  6. DE for Hydrogen DE for Helium exp(-DE/T) exp(-DE/T) Log L T1/2 + + T1/2 T1/2 6 Log T Log T Log T Cooling Function =

  7. Cooling Radius To be compared with In high-density (inner) regions the cooling time is shorter than the galaxy survival time A fractionDmcoolof the available gasWbar Mis able to radiatively cool

  8. Rees & Ostriker 1977 Cores of galaxy Clusters Clusters Galaxies Galaxies Clusters

  9. DM Disks Assume that, durung collapse, the ratio of the ratio is conserved gas Assuming an exponential Surf. Dens. Jgas = Gas Angul. Mom. J = DM Angul. Mom. Assuming centrifugal balance DM angular momentum aquired from tidal torques due to surrounding perturbations For particles in circular orbits lmed=0.04 sl=0.53 Mo, Mao, White 1997 Warren et al.92

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