相关论文: A simple and accurate approximation for the Q stab…
The saturation conditions for bending modes in inhomogeneous thin stellar disks that follow from an analysis of the dispersion relation are compared with those derived from $N$-body simulations. In the central regions of inhomogeneous…
We analyze the shapes of the HI velocity profiles of The HI Nearby Galaxy Survey (THINGS) to study the phase structure of the neutral interstellar medium (ISM) and its relation to global galaxy properties. We use a method analogous to the…
We explore the gravitational instability of clumpy and turbulent gas discs, taking into account the Larson-type scaling laws observed in giant molecular clouds (GMCs) and HI, as well as more general scaling relations. This degree of freedom…
We propose a practical method for analyzing stability of Q-balls for the whole parameter space, which includes the intermediate region between the thin-wall limit and thick-wall limit as well as Q-bubbles (Q-balls in false vacuum), using…
The neutral atomic hydrogen (HI) content of spiral galaxies has been observed to vary with environment, with more HI-deficient spirals residing in high density environments. This can be attributed to environmental effects such as ram…
A combination of classical density-functional theory and thermodynamic perturbation theory is applied to a survey of finite-temperature trends in the relative stabilities of one-component crystals and quasicrystals interacting via effective…
Galaxy evolution is driven to a large extent by interactions and mergers with other galaxies and the gas in galaxies is extremely sensitive to the interactions. One method to measure such interactions uses the quantified morphology of…
We analyze the relationship between the mass of a spherical component and the minimum possible thickness of stable stellar disks. This relationship for real galaxies allows the lower limit on the dark halo mass to be estimated (the thinner…
The near proportionality between HI and dark matter in outer galactic disks prompted us to run N-body simulations of galactic disks in which the observed gas content is supplemented by a dark gas component representing between zero and five…
Recent high-resolution simulations together with theoretical studies of the dynamical evolution of galactic disks have shown that contrary to wide-held beliefs a `live', dynamically responsive, dark halo surrounding a disk does not…
This research paper examines the feasibility and stability of compact stars in the context of $f(\mathcal{Q})$ theory, where $\mathcal{Q}$ represents the non-metricity scalar. To achieve this objective, a static spherical line element is…
Applying the technique of dynamical maps we study the orbital stability of test particles in the Solar System in the space (a,e,i) defined by 0.1<a<38 au, 0<e<0.9 and 0<i<180 identifying the unstable and stable regions. We find stable…
I describe how the dynamics of galactic disks can be inferred by imaging and spectroscopy. Next I demonstrate that the decomposition of the rotation curves of spiral galaxies into the contributions by the various components of the galaxies…
Multi-planetary systems are prevalent in our Galaxy. The long-term stability of such systems may be disrupted if a distant inclined companion excites the eccentricity and inclination of the inner planets via the eccentric Kozai-Lidov…
An earlier paper presented the potentially significant discovery that disturbances in simplified simulations of a stellar disc model that was predicted to be stable in linear theory grew to large amplitude over a long period of time. The…
A model based on disk-stability criteria to determine the number of spiral arms of a general disk galaxy with an exponential disk, a bulge and a dark halo described by a Hernquist model is presented. The multifold rotational symmetry of the…
The study presents a theoretical framework for understanding the role of dark matter on the stability of the galactic disc. We model the galaxy as a two-component system consisting of stars and gas in equilibrium with an external dark…
We analyse a sample of over 1000 stars from 32 fields imaged in the V and I bands with the Wide Field and Planetary Camera, on board of the Hubble Space Telescope. The fields are located at Galactic latitudes | b | >= 15deg and in various…
We explore the connection between the atomic gas fraction, f_atm, and `global disc stability' parameter, q, of galaxies within a fully cosmological context by examining galaxies in the Dark Sage semi-analytic model. The q parameter is…
The $\mathbf{k \cdot p}$ method is a successful approach to obtain band structure, optical and transport properties of semiconductors, and it depends on external parameters that are obtained either from experiments, tight binding or ab…