Context. CO observations have been so far the best way to trace molecular gas in external galaxies, but in low metallicity environments the gas mass deduced could be largely underestimated due to enhanced photodissociation of the CO molecule. Large envelopes of H2 could therefore be missed by CO observations. Aims. At present, the kinematic information of CO data cubes are used to estimate viri...

Not the way one might have thought. In hydrodynamic simulations of galaxy formation, some gas follows the traditionally envisioned route, shock heating to the halo virial temperature before cooling to the much lower temperature of the neutral ISM. But most gas enters galaxies without ever heating close to the virial temperature, gaining thermal energy from weak shocks and adiabatic compression,...

We present a summary of X-ray spectral observations of 30 clusters of galaxies from HEAO-1. There exists strong correlations between X-ray luminosity, Lx , and temperature kT in the form L xaT2 ' 3 . This result combined with the Lx vs central galaxy density relation and the virial theorem indicates that the core radius of the gas should be roughly independent of Lx or KT and that more luminous...

Ensemble non-interacting kinetic energy functional is constructed for spherically symmetric systems. The differential virial theorem is derived for the ensemble. A first-order differential equation for the functional derivative of the ensemble non-interacting kinetic energy functional and the ensemble Pauli potential is presented. This equation can be solved and a special case of the solution p...

Abstract From a new perspective, we reexamine self-gravity and turbulence jointly, in hopes of understanding the physical basis for one most important empirical relations governing clouds interstellar medium (ISM), Larson’s relation relating velocity dispersion ( σ R ) to cloud size ). We report on two key findings. First, correct form is <?CDATA ${\sigma }_{R}={\alpha }_{v}^{1/5}{\sigma }_{\ma...

We give one more proof in two and three space dimensions that the irregular solution of the Schrödinger equation, for zero angular momentum, is in fact the solution of an equation containing an extra “delta function”. We propose another criterium to eliminate the irregular solution which is to require the validity of the virial theorem of which we give a general proof in the classical and quant...

We investigate the particle and kinetic-energy densities for N noninteracting fermions confined in a local potential. Using Gutzwiller's semiclassical Green function, we describe the oscillating parts of the densities in terms of closed nonperiodic classical orbits. We derive universal relations between the oscillating parts of the densities for potentials with spherical symmetry in arbitrary d...

We introduce a simple family of models for representing the dark matter in galaxies. The potential and phase space distribution function are all elementary, while the density is cusped. The models are all hypervirial, that is, the virial theorem holds locally, as well as globally. As an application to dark matter studies, we compute some of the properties of γ-ray sources caused by neutralino s...

By using the scaling method we derive the virial theorem for the relativistic mean field model of nuclei treated in the Thomas–Fermi approach. The Thomas–Fermi solutions statisfy the stability condition against scaling. We apply the formalism to study the excitation energy of the breathing mode in finite nuclei with several relativistic parameter sets of common use. PACS: 21.60.-n; 24.30.Cz; 21...

It is shown from a simple scaling invariance that the ultra-relativistic Hamiltonian (μ=0) does not have bound states when the potential is Coulombic. This supplements the application of the relativistic virial theorem derived by Lucha and Schöberl [1,2] which shows that bound states do not exist for potentials more singular than the Coulomb potential. PACS numbers:03.65.Ge, 12.39.Ki, 12.39.Pn ...