Related papers: Bars do drive spiral density waves
The theoretical understanding of density waves in disk galaxies starts from the classical WKB perturbative analysis of tight-winding perturbations, the key assumption being that the potential due to the density wave is approximately radial.…
When bars form within galaxy formation simulations in the standard cosmological context, dynamical friction with dark matter (DM) causes them to rotate rather slowly. However, almost all observed galactic bars are fast in terms of the ratio…
I use distance- and mass-limited subsamples of the Spitzer Survey of Stellar Structure in Galaxies (S4G) to investigate how the presence of bars in spiral galaxies depends on mass, colour, and gas content and whether large, SDSS-based…
This paper reports on a near-infrared survey of early-type galaxies designed to provide information on bar strengths, bulges, disks, and bar parameters in a statistically well-defined sample of S0-Sa galaxies. Early-type galaxies have the…
The density-wave theory of spiral structure proposes that star formation occurs in or near a spiral-shaped region of higher density that rotates rigidly within the galactic disk at a fixed pattern speed. In most interpretations of this…
A method which we have developed for determining corotation radii, has allowed us to map in detail the radial resonant structures of barred spiral galaxies. Here we have combined this information with new determinations of the bar strength…
Observational data indicate that the Milky Way is a barred spiral galaxy. Computation facilities and availability of data from Galactic surveys stimulate the appearance of models of the Galactic structure. More efforts to build dynamical…
Aims: With the aim of assessing the effects of bars on disc galaxy properties, we present an analysis of different characteristics of spiral galaxies with strong, weak and without bars. Method: We identified barred galaxies from the Sloan…
We test whether the spiral patterns apparent in many large disk galaxies should be thought of as dynamical features that are stationary in a co-rotating frame for > t_{dyn}, as implied by the density wave approach for explaining spiral…
The relative bar torques for 45 galaxies observed at $K$- band with the 4.2m William Herschel Telescope are determined by transforming the light distributions into potentials and deriving the maximum ratios of the tangential forces relative…
We have imaged a sample of 45 face-on spiral galaxies in the K-band, to determine the morphology of the old stellar population, which dominates the mass in the disk. The K-band images of the spiral galaxies have been used to calculate…
We use classifications provided by citizen scientists though Galaxy Zoo to investigate the correlation between bulge size and arm winding in spiral galaxies. Whilst the traditional spiral sequence is based on a combination of both measures,…
The density-wave theory of galactic spiral-arm structure makes a striking prediction that the pitch angle of spiral arms should vary with the wavelength of the galaxy's image. The reason is that stars are born in the density wave but move…
We aim at investigating the formation process of weak bars by measuring their properties in a sample of 29 nearby SAB galaxies, spanning a wide range of morphological types and luminosities. The sample galaxies were selected to have an…
The exact nature of the arms of spiral galaxies is still an open question. It has been widely assumed that spiral arms in galaxies with two distinct symmetrical arms are the products of density waves that propagate around the disk, with the…
For decades, the grand-design SAB spiral galaxy NGC 5248 has been postulated to host a short bar of semi-major axis 22" (1.6 kpc). From dynamical and morphological arguments, we argue, however, that its spiral structure is being driven by a…
We investigate how the properties of spiral arms relate to other fundamental galaxy properties. To this end, we use previously published measurements of those properties, and our own measurements of arm-interarm luminosity contrasts for a…
We built a family of non-axisymmetric potential models for normal non-barred or weakly-barred spiral galaxies as defined in the simplest classification of galaxies: the Hubble sequence. For this purpose a three-dimensional self-gravitating…
Through observations and modeling, we demonstrate how the recently discovered large-scale bar in NGC 5248 generates spiral structure which extends from 10 kpc down to 100 pc, fuels star formation on progressively smaller scales, and drives…
Spiral density wave theory attempts to describe the spiral pattern in spiral galaxies in terms of a long-lived wave structure with a constant pattern speed in order to avoid the winding dilemma. The pattern is consequently a rigidly…