相关论文: Need for context-aware computing in astrophysics

We find a family of exact solutions of Einstein equations describing the field of a static axisymmetric thin disk living in six-dimensional space-time. In particular, we study the disks constructed (by cutting out the central part of the…

Wherever one talks of dark matter, one does so where there is an observable matter and an associated unsolved dynamical issue to be settled. We promote this observation to the status of an axiom and conjecture that there is a dark companion…

Over the past decade, a consensus picture has emerged in which roughly a quarter of the universe consists of dark matter. The observational evidence for the existence of dark matter is reviewed: rotation curves of galaxies, weak lensing…

This thesis deals with the averaging problem in cosmology, which has gained considerable interest in recent years, and is concerned with correction terms (after averaging inhomogeneities) that appear in the Einstein equations when working…

The current standard model of cosmology assumes that the majority of matter in the Universe is made of dark matter, and that the latter is fundamentally different from ordinary matter. Dark matter can in principle explain the rotation of…

A review is given of a priori predictions made for the dynamics of rotating galaxies. One theory - MOND - has had many predictions corroborated by subsequent observations. While it is sometimes possible to offer post hoc explanations for…

Galaxy rotation curve (RC) fitting is an important technique which allows the placement of constraints on different kinds of dark matter (DM) halo models. In the case of non-phenomenological DM profiles with no analytic expressions, the art…

Dark matter is a fundamental constituent of the universe, which is needed to explain a wide variety of astrophysical and cosmological observations. Although the existence of dark matter was first postulated nearly a century ago and its…

Mankind has not yet explained dark matter, the accelerating expansion of the Universe, the 'knee' and 'ankle' of the cosmic ray energy spectrum graph, the low star formation rates of low surface brightness (LSB) dwarf galaxies, the ignition…

The dark-matter candidates of particle physics invariably possess electromagnetic interactions, if only via quantum fluctuations. Taken en masse, dark matter can thus engender an index of refraction which deviates from its vacuum value. Its…

The observed excess of gravitational forces in galaxies and galactic clusters is usually referred as the existence of "dark matter particles" of unknown origin. An alternative explanation of the dark matter effect is presented here by…

Infall of cold dark matter on a galaxy may result in caustic rings where the particle density is enhanced. They may be searched for as features in the galactic rotation curves. Previous studies suggested the evidence for these caustic rings…

An alternative way of explaining astrophysical observations without dark matter is proposed. In the braneworld scenario, where our universe is visualised as a 4-dimensional hypersurface embedded in a higher dimensional spacetime, the…

During the last ten years astrophysical cosmology has brought three remarkable results of deep impact for fundamental physics: the existence of non-baryonic dark matter, the (nearly) flatness of space, the domination of the density of the…

A PhD student is locked inside a box, imitating a quantum system by mimicking the measurement statistics of any viable observable nominated by external observers. Inside a second box lies a genuine quantum system. Either box can be used to…

This paper discusses the observed at rotation curves of galaxies in the context of noncommutative geometry. The energy density of such a geometry is diffused throughout a region due to the uncertainty encoded in the coordinate commutator.…

The formation of disk galaxies is one of the most outstanding problems in modern astrophysics and cosmology. We review the progress made by numerical simulations carried out on large parallel supercomputers. Recent progress stems from a…

The purpose of this paper is to seek a connection between noncommutative geometry, an offshoot of string theory, and certain aspects of dark matter and dark energy. The former case is based on a simple mathematical argument showing that the…

The recent paper by Lee and Lee (2004) may strongly leave the impression that astronomers have established that the rotation curves of spiral galaxies are flat. We show that the old paradigm of Flat Rotation Curves lacks, today, any…

We investigate the radial behavior of galactic rotation curves by a Fourth Order Gravity adding also the Dark Matter component. The Fourth Order Gravity is a Lagrangian containing the Ricci scalar, the Ricci and Riemann tensor, but the…