The application of high end computing to astrophysical problems, mainly in the galactic environment, is a well established topic at the Dep. of Physics of Sapienza Univ. of Roma. The main scientific subject is the physics of self gravitating systems, whose specific subtopics are:

i) celestial mechanics and interplanetary probe transfers in the solar system; ii) dynamics of globular clusters and of globular cluster systems; iii) nuclear clusters formation and evolution; iv) massive black hole formation and evolution; v) young star cluster early evolution.

Many relevant scientific results in these fields have been reached by our group by means of our simulation techniques. In particular, we have developed various numerical codes to follow the dynamics of dry systems (purely stellar systems). We have followed a phylosophy a bit different from that of other groups in that we preferred developing, testing and running our own original codes rather than resorting to freely available simulation codes and packages.

In this web page we address to various codes of ours aiming at the study of the evolution of classic, newtonian N-body systems, in presence or abscence of a gaseous component.

"DRY" N-BODY CODES

For "dry" N-body code we mean a numerical code which evolves a system of N point masses in vacuum.

As ``dry'' N-body codes we present below four different high-precision, direct summation codes, particularly apt to follow the evolution of collisional stellar systems with high computational efficiency:

• ARW: a regularized few-body code (N < 400) originally produced by S. Mikkola and further modified by P. Chassonnery and R. Capuzzo-Dolcetta. This is the user manual .

• NBSymple: a symplectic, 6^th order N-body integrator (authors R. Capuzzo-Dolcetta and A. Mastrobuono-Battisti, see this paper).

• RK8NB: a Runge-Kutta 8^th order N-body integrator (authors R. Capuzzo-Dolcetta and M. Cristiano; see this paper ).

• HiGPUs: a Hermite's, 6^th order individual time stepping N-body integrator (authors R. Capuzzo-Dolcetta, M. Spera and D. Punzo, see this paper).

Two of them are apt to work in parallel CPU+GPU system. RK8NB is a serial code.

GAS, SELF-GRAVITATING SPH CODES

One of them, ATD, is an adaptive SPH tree-code developed by R. Capuzzo-Dolcetta and P. Miocchi (see this paper), which constitutes an improvement of the classic Barnes and Hut (1986) tree algorithm scheme.

A modern and optimized SPH tree code recently developed by us is

• GaSPH, developed by R. Capuzzo-Dolcetta, L.D. Pinto and G. Magni (see this paper).