ar X iv : a st ro - p h / 05 11 73 8 v 2 2 9 N ov 2 00 5 Equilibrium of large astrophysical structures in the Newton - Hooke spacetime

ar X iv : a st ro - p h / 05 11 73 8 v 1 2 5 N ov 2 00 5 Equilibrium of large astrophysical structures in the Newton - Hooke spacetime

Using the scalar and tensor virial equations, the Lane-Emden equation expressing the hydrostatic equilibrium and small oscillations around the equilibrium, we show how the cosmological constant Λ affects various astrophysical quantities important for large matter conglomeration in the universe. Among others we examine the effect of Λ on the polytropic equation of state for spherically symmetric...

ar X iv : a st ro - p h / 05 11 73 8 v 3 1 9 Ja n 20 06 Equilibrium of large astrophysical structures in the Newton - Hooke spacetime

Using the scalar and tensor virial equations, the Lane-Emden equation expressing the hydrostatic equilibrium and small oscillations around the equilibrium, we show how the cosmological constant Λ affects various astrophysical quantities important for large matter conglomeration in the universe. Among others we examine the effect of Λ on the polytropic equation of state for spherically symmetric...

ar X iv : a st ro - p h / 05 11 15 9 v 1 6 N ov 2 00 5 1 EMISSION MEASURE DISTRIBUTION AND ABUNDANCES MEASUREMENTS DURING HIGH - T FLARES

The RSCVn system σ Geminorum was observed by XMM-Newton on April 2001 during a large flare. We model the emission measure distribution (EMD) during the flare and during a quiescence period. In the flare, a two phase behaviour is found in which the cool plasma (kT < 2 keV) is not disturbed while a large hot component , at temperatues of kT > 3 keV emerges. Fundamental limitations on EMD modeling...

ar X iv : a st ro - p h / 01 11 13 6 v 1 7 N ov 2 00 1 1 Active Optics in Modern , Large Optical Telescopes

ar X iv : a st ro - p h / 04 11 59 5 v 1 2 2 N ov 2 00 4 Geometry of Dynamical Systems †

We propose a geometrical approach to the investigation of Hamiltonian systems on (Pseudo) Riemannian manifolds. A new geometrical criterion of instability and chaos is proposed. This approach is more generic than well known reduction to the geodesic flow. It is applicable to various astrophysical and cosmological problems.