Related papers: Disc heating in NGC 2985
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…
We present new models for the formation of disk galaxies that improve upon previous models by following the detailed accretion and cooling of the baryonic mass, and by using realistic distributions of specific angular momentum. Under the…
In this talk I will summarize some of the work that the CfA group has done to study the structure of the water masers in the accretion disk of NGC 4258. A series of 18 epochs of VLBA data taken from 1997.3 to 2000.8 were used for this…
Using N-body simulations of the Galactic disks, we qualitatively study how the metallicity distributions of the thick and thin disk stars are modified by radial mixing induced by the bar and spiral arms. We show that radial mixing drives a…
The stellar disc kinematics in a sample of fifteen intermediate- to late-type edge-on spiral galaxies are studied using a dynamical modeling technique. The sample covers a substantial range in maximum rotation velocity and deprojected…
The neutral hydrogen line profiles along the major axis of the nearby spiral galaxy NGC 2403 show a wing towards the sytemic velocity. This asymmetry can be explained with the presence of an abnormally thick HI disk (FWHM ~ 5 kpc) or with a…
In a previous paper (Olling 1995, astro-ph/9505002) a method was developed to determine the shapes of dark matter halos of spiral galaxies from an accurate determination of the rotation curve, the flaring of the gas layer and the velocity…
We consider seven distant galaxies with clearly evident spiral structure from HST images. Three of these were chosen from Vogt et al. (1996) (VFP) and have measured rotational velocities. Five were chosen from the Medium Deep Survey and are…
We have applied the "Synthetic Field Method" on a sample of ~20 nearby galaxies in order to determine the opacity of their disks. We present preliminary results on the radial dependence of cold dust absorption for 3 examples. The spirals…
The standard method of measuring the galaxy pairwise velocity dispersion on small scales is heavily weighted by the densest regions in a way that is difficult to calibrate. We propose a new statistic which measures the small-scale velocity…
Gas accretion, hot ($\sim 10^6\,{\rm K}$) atmospheres, and a tilt between the rotation axes of the disc and the atmosphere are all common predictions of standard galaxy evolution theory for massive star-forming galaxies at low redshift.…
We present V-band surface photometry and major-axis kinematics of stars and ionized gas of three early-type spiral galaxies, namely NGC 772, NGC 3898 and NGC 7782. For each galaxy we built a self-consistent Jeans model for the stellar…
Models of disk galaxy formation commonly predict the existence of an extended reservoir of accreted hot gas surrounding massive spirals at low redshift. As a test of these models, we use X-ray and H-alpha data of the two massive, quiescent…
When astronomers study the dark matter halos of spiral galaxies, they normally assume that the disk mass-to-light ratio is *constant*. We describe a method of analyzing the kinematics of planetary nebulae (PNe) in nearby face-on spiral…
We explore the dependence of the ratio of a galaxy's circular velocity, Vcirc, to its central velocity dispersion, sigma_0, on morphology, or equivalently total light concentration. Such a dependence is expected if light traces the mass.…
We propose that turbulent heating, wave pressure and gas exchanges between different regions of disks play a dominant role in determining the preferred, quasi-equilibrium, self-similar states of gas disks on large-scales. We present simple…
We study the vertical heating and thickening of galaxy disks due to accretion of small satellites. Our simulations are restricted to axial symmetry, which largely eliminates numerical evolution of the target galaxy but requires the…
Non-axisymmetric components, such as spirals and central bars, play a major role in shaping galactic discs. An important aspect of the disc secular evolution driven by these perturbers is the radial migration of stars. It has been suggested…
We present an application of a new set of detailed, self-consistent, dynamical models for disc galaxies. We start from the hypothesis that each galaxy can be decomposed in a bulge, following the r^{1/4} law, and a disc with an exponential…
Our understanding of how the size of galaxies has evolved over cosmic time is based on the use of the half-light (effective) radius as a size indicator. Although the half-light radius has many advantages for structurally parameterising…