Eve C Ostriker

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The debate over whether kilometer-sized solids, or planetesi-mals, assemble by collision-induced chemical sticking or by gravity-driven unstable modes remains unsettled. In light of recent work showing that gravitational growth can occur despite turbulent stirring, we critically evaluate the collisional hypothesis. Impact speeds in protoplanetary disks(More)
We review current understanding of star formation, outlining an overall theoretical framework and the observations that motivate it. A conception of star formation has emerged in which turbulence plays a dual role, both creating overdensities to initiate gravitational contraction or collapse, and countering the effects of gravity in these overdense regions.(More)
The under-abundance of very massive galaxies in the Universe is frequently attributed to the effect of galactic winds. Although ionized galactic winds are readily observable, most of the expelled mass (that is, the total mass flowing out from the nuclear region) is likely to be in atomic and molecular phases that are cooler than the ionized phases.(More)
We review recent results from numerical simulations and related models of MHD turbulence in the interstellar medium (ISM) and in molecular clouds. We discuss the implications of turbulence for the processes of cloud formation and evolution, and the determination of clouds' physical properties. Numerical simulations of the turbulent ISM to date have included(More)
We analyze the spectral properties of driven, supersonic compressible magne-tohydrodynamic (MHD) turbulence obtained via high-resolution numerical experiments , for application to understanding the dynamics of giant molecular clouds. Via angle-averaged power spectra, we characterize the transfer of energy from the intermediate, driving scales down to(More)
We describe hot, optically-thin solutions for one-temperature accretion disks around black holes. We include cooling by synchrotron, bremsstrahlung, and Comptonization. Our solutions are thermally and viscously stable, with gas temperatures on the order of T ∼ 10 9 − 10 10.7 K. The thermal stability is a direct result of the inclusion of synchrotron(More)
We present two-dimensional hydrodynamical simulations of both jet-and wind-driven models for protostellar outflows in order to make detailed comparisons to the kinematics of observed molecular outflows. The simulations are performed with the ZEUS-2D hydrodynamical code using a simplified equation of state, simplified cooling and no external heating, and no(More)
This paper reviews current theoretical work on the various stages of accretion in protostars, and the relationship of these ideal stages to the spectral classes of observed protostellar systems. I discuss scaling relationships that have been obtained for models of pre-stellar cores as they evolve by ambipolar diffusion toward a central singularity, and(More)
Using self-consistent magnetohydrodynamic (MHD) simulations, we explore the hypothesis that nonlinear MHD waves dominate the internal dynamics of galactic molecular clouds. Our models employ an isothermal equation of state and allow for self-gravity. We adopt " slab-symmetry, " which permits motions v ⊥ and fields B ⊥ perpendicular to the mean field, but(More)