NonEquilibrium Ionization in Metal Ion Absorbers and in

Non-Equilibrium Ionization in Metal Ion Absorbers and in Post-Shock Cooling Layers Gnat & Sternberg 2007, Ap. JS, 168, 213 Gnat & Sternberg 2008, Ap. J submitted Orly Gnat (Caltech) with Amiel Sternberg (Tel-Aviv University) Oct 17, 2008

Non–Equilibrium Radiative Cooling • Cooling is faster than recombination (tc<<tr) • Gas stays “over-ionized” • Modified ionization affects cooling rates: for over-ionized gas cooling is suppressed • Cooling rate depends on metallicity More metals ⇒ faster cooling ⇒ further out of equilibrium Oct 17, 2008 Ap. JS 168, 213

Numerical Computation 6 K. • Cooling from CIE at T>5 x 10 ~ • Follow time-dependent ionization dxi/dt=… H He • The energy equation (Cooling) C N O d. T/dt=… Ne Mg • Step 1: No Photoionization Si S Fe • dxi/d. T independent of density …But depends on metallicity Oct 17, 2008 Ap. JS 168, 213

Results: Ionization - Hydrogen Equilibrium Non-Equilibrium 100 time 10 -1 10 -2 104 105 106 104 Temperature (K) 105 Temperature (K) Recombination Lag Oct 17, 2008 Ap. JS 168, 213 106

Results: Ionization - Carbon Equilibrium Non-Equilibrium 100 10 -1 10 -2 104 105 106 104 Temperature (K) Oct 17, 2008 105 Temperature (K) Ap. JS 168, 213 106

Results: CIE Cooling Metal Line Cooling Leq (erg cm 3 s-1) cooling efficiency 10 -21 10 -22 Z=1 Z = 10 -2 Z = 10 -3 H Lya He Cooling 10 -23 10 -24 104 Oct 17, 2008 Bremsstrahlung 105 106 Temperature (K) 107 108

Results: Non-Equilibrium Cooling Equilibrium Non-Equilibrium Oct 17, 2008

Local Metal-Ion Absorbers Oct 17, 2008 Cooling Flows Shock Ionization log ( CIV / OVI ) Fox et al. 2005 Ap. J 630, 332 Turbulent Mixing Layers Conductive Interfaces log ( NV / OVI ) Ap. JS 168, 213

High Velocity Metal Absorbers Fox et al. 2005 Ap. J, 630, 332 Oct 17, 2008

Time-Dependent Cooling - Summary • Equilibrium and Non-Equilibrium Ionization States & Cooling Efficiencies of H, He, C, N, O, Ne, Mg, Si, S, & Fe, For 104 < T < 108 K and 10 -3 < Z < 2 solar. • Isochoric / Isobaric – conditions & results. • Impact of Self Radiation. http: //wise-obs. tau. ac. il/~orlyg/cooling/ Oct 17, 2008 Ap. JS 168, 213

Step 2: Steady Flows of Cooling Gas • Integrated metal-ion cooling columns in steady flows of cooling gas Oct 17, 2008

Post Shock Cooling Layers • Radiative transfer ⇒ Photoionization, heating • Ionization: Auger • Precursor shock Pre-shock Post-shock gas T(x) <— upstream Oct 17, 2008 • Dynamics downstream —>

Post-Shock Cooling Layers • Two extremes: – No B field - explicitly follow Rankine-Hugoniot continuity eqns: Mass Momentum Energy Nearly isobaric flow: P∞ = 4/3 P 0 – Strong B field - isochoric evolution. Oct 17, 2008

Ts=5 x 106 K Z=0. 1 n. H=0. 1 cm-3 Oct 17, 2008 (Photoionized) Radiative Precursor Post-Shock Cooling: Shock Structure High-T Radiative Zone Non-eq Cooling Zone The Photoabsorption Zone

Post-Shock Cooling: Shock Structure Gas Metallicity Shock temperature Oct 17, 2008 Magnetic field

Post-Shock Cooling: Emitted Radiation Oct 17, 2008

Post-Shock Cooling: Column Densities Oct 17, 2008

Gnat & Sternberg 2008 • Shock Structure, Profiles, Scaling Relations • Ion Fractions • Cooling and Heating • Integrated Column Densities • Columns in Precursors Thank you ! Oct 17, 2008