Detailed Study of a Turbulent multiphase multicomponent ISM

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1 Detailed Study of a Turbulent multiphase multicomponent ISM Dieter Breitschwerdt

2 Collaborators Miguel de Avillez (Evora, Portugal) Verena Baumgartner (Vienna, Austria) Jan Bolte (TU Berlin, Germany) Jenny Feige (Vienna, Austria) Stefan Harfst (TU Berlin, Germany) Beate Patzer (TU Berlin, Germany) Ingo Philipp (Vienna, Austria) Michael Schulreich (TU Berlin, Germany) Robert Tautz (TU Berlin, Germany)

3 M33: composite Chandra & HST filaments structure on scales turbulence wide range of temperatures, densities multiphase gas, magnetic fields, cosmic rays, dust multicomponent

4 High Resolution ISM Simulations Solve full HD/MHD equations on a large grid: 1 kpc 1kpc ± 10 kpc (Δx=0.5 pc or less) Fully time-dependent non-equilibrium ionization (NEI) structure Type Ia,b,c/II SNe random + clustered in disk Background heating due to diffuse UV photon field Gravitational field by stars + self-gravity SFR local density/temp.: n >10 cm -3 /T<100 K Generate stars according to an IMF Formation and motion of OB associations ( random velocity of stars) Evolution of computational volume for τ ~ 400 My sufficiently long to erase memory of initial conditions! 3D calculations on parallel processors with adaptive mesh refinement (AMR)

5 HD-Evolution of ISM Collective effect of SNe induces break-out of ISM disk gas galactic fountain (cf. intermediate velocity clouds) reduce disk pressure Density and temperature distribution shows structures on all scales (cf. observation of filaments) shear flow due to expanding SNRs generate high level of turbulence coupling of scales Cloud formation by shock compressed layers clouds are transient features generation of new stars large amount of gas in thermally unstable phases volume filling factor of HIM ~ 20% no pressure equilibrium! y Avillez & Breitschwerdt, 2010 x

6 MHD-Evolution of ISM B^ Avillez & Breitschwerdt, 2005 n B-field // to disk cannot prevent outflow into halo; Halo density is inhomogeneous (Fountain) Which pressure determines ISM dynamics? For T < 200 K: magnetic pressure dominates, for 200 K < T < 10 6 K ram pressure dominates, for T>10 6 K thermal pressure dominates

7 Non-equilibrium ionization (NEI) structure of ISM (I) optically thin hot plasmas: continuum + line spectrum collisional ionization equilibrium (CIE): ionization by collisions (3-body process) is balanced by radiative recombination no detailed balancing, because atomic time scales are different plasma is driven out of CIE non-equilibium ionization (NEI) structure particularly striking effect: fast adiabatic cooling like in a galactic fountain or wind (Breitschwerdt & Schmutzler, 1994) CIE Böhringer 1998 NEI - radiative recombination collisional ionization Top: CIE vs. NEI plasma emission codes; in CIE, plasma emission can be calculated (in coronal approx., i.e. n e < 10 4 cm -3 ) once and for all if n e, T e and Z are given; in NEI Z + astrophysical model for dynamical evolution is required! Left: Animation of collisional ionization by electrons

8 NEI structure of ISM (II) Avillez & Breitschwerdt 2010 CIE cooling curves are no longer valid cooling depends on the thermal and dynamical conditions of the plasma Cooling depends on the history of the plasma, i.e. on the ionization stages present Ionization structure varies from place to place and with time multitude of different cooling functions! delayed recombination: plasma is overionized due to slow recomb. of high ionization stages typical for very hot cooling plasmas delayed ionization: plasma is underionized due to slow ionization of neutral plasma typical for cold plasmas collisionally ionized by shocks X-ray observations of diffuse hot plasma show signs of delayed recombination log Λ N [erg cm 3 s -1 ] T o = 10 5 K CIE NEI A B C D E log T [K] Top: Midplane cut of NEI simulations marking regions of different temperatures: 10 5 K (A-E), K (F-J), 10 6 K (K-O) Bottom: Cooling curves of different places with different initial temperatures; dotted and dashed lines are CIE and NEI curves of an initially completely ionized plasma T o = K CIE NEI F G H I J log T [K] T o = 10 6 K CIE NEI K L M N O log T [K]

9 SPP 1573-Project Suggestions (I) Fundamental studies of turbulence in large and small scale high resolution 3D-AMR ISM simulations Turbulent mixing of chemically enriched material (e.g. 60 Fe from SN explosions in the Local Bubble) chemical evolution of ISM Formation of molecular clouds in large scale ISM flows connect small to large scales (see Harfst) Avillez & Breitschwerdt (2007) Integral scale in ISM turbulence 60 Fe measured in ferromanganese ocean crust LCC UCL Breitschwerdt et al Knie et al. 2004

10 SPP 1573-Project Suggestions (II) Diffuse X-ray and UV emission from ISM plasmas NEI simulations and comparisons with observations (see Sasaki) Cosmic Ray hydrodynamics in SN driven and magnetized ISM Galactic Centre (Chandra, HST, Spitzer) Cosmic Ray acceleration in galactic outflow shocks Cosmic Ray acceleration galactic outflows (Dorfi & Breitschwerdt, 2010)

11 SPP 1573: Physics of the ISM Proposed research project: Title (tentative): Dust nucleation in outflows of AGB stars The role of carbides PI: B. Patzer Institute: Zentrum für Astronomie und Astrophysik, TU Berlin Funding: 1 PhD position Science themes addressed: Sources of interstellar dust (2.2.4) Star ISM interaction (2.2.5) DFT calculation Ti 14 C 13

12 Suggestions & Collaborations on Topics of Common Interest Welcome