We characterize the nature of thin, axisymmetric, inviscid, accretion flows of cold adiabatic gas with zero specific energy in the vicinity of a black hole by the specific angular momentum. Using two-dimensional hydrodynamic simulations in cylindrical geometry, we present various regimes in which the accretion flows behave distinctly differently. When the flow has a small angular momentum (λ<∼λ...

The final stage in the formation of terrestrial planets consists of the accumulation of ∼ 1000-km “planetary embryos” and a swarm of billions of 1-10 km “planetesimals.” During this process, water-rich material is accreted by the terrestrial planets via impacts of water-rich bodies from beyond roughly 2.5 AU. We present results from five high-resolution dynamical simulations. These start from 1...

Site U1325 (Prospectus Site CAS-02C) is located near the southwestern end of the marginperpendicular transect established during Expedition 311 and is within a major slope basin that developed eastward of the deformation front behind a steep ridge of accreted sediments. Bathymetry data show that the seafloor in the western part of this slope basin is relatively flat with water depths around 220...

We study the evolution of the magnetic field of an accreting neutron star in the frozen field and incompressible fluid approximations. The plasma is accreted onto two polar caps and squeezes some of the surface material of the neutron star toward the equator. The frozen B-field is then pushed toward the equator and is eventually buried there. The magnetic field within the polar cap areas, which...

Context. Mergers of neutron stars (NS) and black holes (BH) are among the strongest sources of gravitational waves and are potential central engines for short gamma-ray bursts. Aims. We aim to compare the general relativistic (GR) results by other groups with Newtonian calculations of models with equivalent parameters. We vary the mass ratios between NS and BH and the compactness of the NS. The...

We have performed a detailed analysis of the local super-massive black-hole (SMBH) mass function based on both kinematic and photometric data and derived an accurate analytical fit in the range 10 6 MBH/M⊙ 6 5 × 10 . We find a total SMBH mass density of (4.2 ± 1.1)× 105M⊙/Mpc , about 25% of which is contributed by SMBHs residing in bulges of late type galaxies. Exploiting up-to-date luminosity ...

We present six simulations of galactic stellar haloes formed by the tidal disruption of accreted dwarf galaxies in a fully cosmological setting. Our model is based on the Aquarius project, a suite of high-resolution N-body simulations of individual dark matter haloes. We tag subsets of particles in these simulations with stellar populations predicted by the GALFORM semianalytic model. Our metho...

We characterize the nature of thin, axisymmetric, inviscid, accretion flows of cold adiabatic gas with zero specific energy in the vicinity of a black hole by the specific angular momentum. Using two-dimensional hydrodynamic simulations in cylindrical geometry, we present various regimes in which the accretion flows behave distinctly differently. When the flow has a small angular momentum (λ<∼λ...

We analysed Rossi X-ray Timing Explorer observations of the accretion-powered 401 Hz pulsar SAX J1808.4−3658, in order to precisely determine the source distance. While the fluences for the five transient outbursts observed from 1996 were constant to within the uncertainties, the outburst interval varied signficantly, so that the time-averaged flux (and accretion rate) decreased by around 40%. ...

In 3-d SPH simulations of the coalescence of a quark star with a pseudo-Newtonian black hole all of the quark matter is quickly accreted by the black hole. The AlparMadsen-Caldwell-Friedman argument against the existence of quark stars may need to be re-examined.