The Cold Dark Matter (CDM) structure formation model predicts that about 5-10 percent of a typical galactic halo mass ∼ 10M⊙is in substructures with a mass . 10M⊙. To directly detect such substructures, we propose to observe dust continuum emission from a strongly lensed QSO-host galaxy using a large submillimeter interferometer array with a high angular resolution ∼ 0.01arcsec such as the plan...

X-ray emitting clusters of galaxies are considered in the context of modified Newtonian dynamics (MOND). I show that self-gravitating isothermal gas spheres are not good representations of rich clusters with respect to the radial gas density distribution as indicated by the X-ray surface brightness. Pure gas spheres with a density distribution described by a β model, as observed, also fail beca...

Hydrodynamical calculations in three space dimensions of the collapse of an isothermal, rotating 1 M⊙ protostellar cloud are presented. The initial density stratification is a power law with density ρ ∝ r, with p = 1. The case of the singular isothermal sphere (p = 2) is not considered; however p = 1 has been shown observationally to be a good representation of the density distribution in molec...

Aims. We determine the central mass distribution of galaxy cluster RX J1347−1145 using strong gravitational lensing. Methods. High resolution HST/ACS images of the galaxy cluster RX J1347−1145 have enabled us to identify several new multiple image candidates in the cluster, including a 5 image system with a central image. The multiple images allow us to construct an accurate 2-dimensional mass ...

The present article serves the purpose of pursuing Geometrization of heat flow on volumetrically isothermal manifold by means of RF approach. In this article, we have analyzed the evolution of heat equation in a 3-dimensional smooth isothermal manifold bearing characteristics of Riemannian manifold and fundamental properties of thermodynamic systems. By making use of the notions of various curva...

The magnification of distant sources by mass clumps at lower (z ≤ 1) redshifts is calculated analytically. The clumps are initially assumed to be galaxy group isothermal spheres with properties inferred from an extensive survey. The average effect, which includes strong lensing, is exactly counteracted by the beam divergence in between clumps (more precisely, the average reciprocal magnificatio...

We study numerically the collapse of nonrotating self-gravitating magnetized singular isothermal toroids characterized by sound speed, a, and level of magnetic to thermal support,H0. In qualitative agreement with treatments by Galli & Shu and other workers, we find that the infalling material is deflected by the field lines toward the equatorial plane, creating a high-density flattened structur...

We examine whether a cosmologically significant distribution of dark galaxy group or cluster-sized objects can have an optical depth for multiple imaging of distant background sources which is comparable to that from known galaxies while at the same time producing angular splittings of the same order of magnitude. Our purpose is to explore whether such objects could realistically account for so...

An analytical model is presented for the postcollapse equilibrium structure of virialized objects which condense out of a low-density cosmological background universe, either matter-dominated or flat with a cosmological constant. This generalizes the model we derived previously for an Einstein-de Sitter (EdS) universe. The model is based upon the assumption that cosmological haloes form from th...

We present numerical simulations of the evolution of low-mass, isothermal, molecular cores which are subjected to an increase in external pressure Pext. If Pext increases very slowly, the core approaches instability quite quasistatically. However, for larger (but still quite modest) dPext/dt a compression wave is driven into the core, thereby triggering collapse from the outside in. If collapse...