One of the main astrophysical processes leading to strong emission of gravitational waves to be detected by the future space-borne interferometer LISA is the capture of a compact star by a black hole with a mass of a few million solar masses in the center of a galaxy. In previous studies, main sequence stars were thought not to contribute because they suffer from early tidal disruption. Here we...

The approximate computation of all gravitational forces between N interacting particles via the fast multipole method (FMM) can be made as accurate as direct summation, but requires less thanO (N) operations. FMM groups particles into spatially bounded cells and uses cell-cell interactions to approximate the force at any position within the sink cell by a Taylor expansion obtained from the mult...

We study a three dimensional continuous model of gravitating matter rotating at constant angular velocity. In the rotating reference frame, by a finite dimensional reduction, we prove the existence of non radial stationary solutions whose supports are made of an arbitrarily large number of disjoint compact sets, in the low angular velocity and large scale limit. At first order, the solutions be...

I provide some background about recent efforts made in modeling dense stellar systems, within the context of the MODEST initiative. During the last four years, we have seen more than fifteen MODEST workshops, with an attendance between twenty and a hundred participants, and topics ranging from very specialized discussions to rather general overviews. 1. Dense Stellar Systems The study of star c...

We determine the response of a self-similar isothermal stellar system to small adiabatic gravitational perturbations. For odd spherical harmonics, the response is identical to the response of the analogous isothermal fluid system. For even spherical harmonics, the response can be regarded as an infinite series of wavetrains in log r, implying alternating compression and rarefaction in equal log...

We explore the possibility that extended disks, such as that recently discovered in M31, are the result of a single dwarf (10–10M⊙) satellite merger. We conduct N-body simulations of dwarf NFW halos with embedded spheriodal stellar components on co-planar, prograde orbits in a M31-like host galaxy. As the orbit decays due to dynamical friction and the system is disrupted, the stellar particles ...

We compare the statistical properties of J=1→0 CO spectra observed in the Perseus Molecular Cloud with synthetic J=1→0 CO spectra, computed solving the non–LTE radiative transfer problem for a model cloud obtained as solutions of the three dimensional magneto–hydrodynamic (MHD) equations. The model cloud is a randomly forced super–Alfvénic and highly super–sonic turbulent isothermal flow. The p...

The existence of power law statistics in solar and stellar flares has prompted the suggestion that solar and stellar coronae are in a self-organized critical state, but the physical foundation of this theory is lacking. We present observational evidence from 107 flare events in 37 sun-like stars that solar and stellar coronae self-organize into a critical state set by a bifurcation in the dynam...

Note to readers: Those unfamiliar with common terms from stellar dynamics like softening, collision, regularization, etc., should probably read the glossary rst. (Page 23.)