Related papers: Virial shocks in galactic haloes?
Using one-dimensional hydrodynamic simulations including interstellar heating, cooling, and thermal conduction, we investigate nonlinear evolution of gas flow across galactic spiral arms. We model the gas as a non-self-gravitating,…
Motivated by recent observation of Lanzetta et al. that most luminous galaxies at low redshifts produce $\lya$ absorption at impact parameter $l\lsim 160 \kpch$, we propose that these absorbers are clouds confined by the pressure of ambient…
We study the survival of substructures (clumps) within larger self-gravitating dark matter halos. Building on scaling relations obtained from N-body calculations of violent relaxation, we argue that the tidal field of galaxies and halos can…
We investigate the internal structure of cold dark matter halos using high resolution N-body simulations. As the mass and force resolution are increased, halo density profiles become steeper, asymptoting to a slope of $\sim -4/3$ in the…
Large dynamic range numerical simulations of atomic cooling driven collapse of gas in pre-galactic DM haloes with T_vir ~ 10000 K show that the gas loses 90% and more of its angular momentum before rotational support sets in. In a fraction…
We use high-resolution Eulerian simulations to study the stability of cold gas flows in a galaxy size dark matter halo (10^12 Msun) at redshift z=2. Our simulations show that a cold stream penetrating a hot gaseous halo is stable against…
Simulations of cosmological filamentary accretion reveal flows ("streams") of warm gas, ~$10^4$ K, which are efficient in bringing gas into galaxies. We present a phenomenological scenario where gas in such flows -- if it is shocked as it…
The observed flaring of HI disk in the outer region of galaxies has been used in the past to determine the shape of the dark matter halo. Previous studies based on this concept suggest a slightly oblate halo (axis ratio ~ 0.8) for our…
We explore analytically the structure of relativistic shock and solitary wave solutions in collisionless plasmas. In the wave frame of reference, a cold plasma is flowing from one end and impacting on a low velocity plasma. First we show…
Galaxy clusters are thought to grow by accreting mass through large-scale, strong, yet elusive, virial shocks. Such a shock is expected to accelerate relativistic electrons, thus generating a spectrally-flat leptonic virial-ring. However,…
We investigate the ab-initio formation of super-massive stars in a pristine atomic cooling halo. The halo is extracted from a larger self-consistent parent simulation. The halo remains metal-free and star formation is suppressed due to a…
Cosmological simulations show that, at the present time, a substantial fraction of the gas in the intergalactic medium (IGM) has been shock-heated to T>10^5 K. Here we develop an analytic model to describe the fraction of shocked,…
Heating of virialized gas by streaming cosmic rays (CRs) may be energetically important in galaxy halos, groups and clusters. We present a linear thermal stability analysis of plasmas heated by streaming CRs. We separately treat equilibria…
Within protogalaxies, thermal instability leads to the formation of a population of cool fragments, confined by the pressure of residual hot gas. The hot gas remains in quasi-hydrostatic equilibrium, at approximately the virial temperature…
Theoretical studies of structure formation find an inverse proportionality between the concentration of dark matter haloes and virial mass. This trend has been recently confirmed for virial masses Mvir > ~6e12 Msun by the observation of the…
We improve on our earlier dynamical estimate of the virial masses of the haloes of Lyman-break galaxies (LBGs) at redshift z=3 by accounting for the effects of seeing, slit width, and observational uncertainties. From an analysis of the…
We investigate the formation of spherical cosmological structures following both dark matter and gas components. We focus on the dynamical aspect of the collapse assuming an adiabatic, $\gamma = 5/3$, fully ionized primordial plasma. We use…
We use idealized 3D hydrodynamic simulations to study the dynamics and thermal structure of the circumgalactic medium (CGM). Our simulations quantify the role of cooling, stellar feedback driven galactic winds and cosmological gas accretion…
We study the complete dynamical evolution of hot interstellar gas in massive elliptical galaxies born into a simple flat universe beginning with an overdense perturbation. Within the turn-around radius dark matter flows in a self-similar…
An explosively generated shockwave with time-dependent radius $R(t)$ is characterized by a phase in which the shocked gas becomes radiative with an effective adiabatic index $\gamma \simeq 1$. Using the result that the post-shock gas is…