X iv : a st ro - p h / 99 09 07 9 v 1 3 S ep 1 99 9 A New Object - Weighted Measure of the Small - Scale Velocity Dispersion

ar X iv : a st ro - p h / 99 08 17 3 v 1 1 6 A ug 1 99 9 On the Verge of Coalescence : a Dusty Group of Galaxies

We found a new, very compact group of galaxies characterized by a median projected separation between galaxies of 5.2/h kpc and a very low velocity dispersion. All the observed member galaxies show emission line spectra and a disturbed morphology. From these properties it emerges that this compact group is in an extremely advanced stage of evolution.

ar X iv : a st ro - p h / 96 06 15 5 v 2 6 S ep 1 99 6 Comment on “ Dispersion Velocity of Galactic Dark Matter Particles ”

ar X iv : a st ro - p h / 99 09 00 9 v 1 1 S ep 1 99 9 Any Recent Progress in the Theory of Pulsating Stars ? Alfred

To answer the topical question we survey synoptically the recent literature in pulsation theory. We restrict the topics to those which are not dealt with otherwise in this volume. We address research on roAp stars, EC 14026 variables, strange modes, luminous blue variables, pulsation-rotation coupling, and pulsations in compact objects seen from the classical, as well as the relativistic, viewp...

ar X iv : a st ro - p h / 99 09 05 7 v 1 2 S ep 1 99 9 Using Perturbative Least Action to Run N Body Simulations Back in Time

In this report, we present a new method for reconstructing N body initial conditions from a proscribed final density field. This method, Perturbative Least Action (PLA) is similar to traditional least action approaches, except that orbits of particles are found as expansions around previously determined and physically motivated orbits.

ar X iv : a st ro - p h / 98 09 06 4 v 1 5 S ep 1 99 8 Velocity Dispersion of the Gravitational Lens 0957 + 561 1

0957+561 is the first gravitational lens system to be discovered and first for which a time delay was measured. Because the system is unusually rich in observables such as image positions, fluxes, VLBI structure, and polarization it has been modelled quite extensively. However, since it resides in a cluster providing substantial convergence, the velocity dispersion of the lensing galaxy is an i...