rotation curve

Typical rotation curveclick for a larger image
Typical rotation curve

rotation curve

A plot of the rotational velocity, V , as a function of radius, R , in a spiral galaxy (see illustration). Rotation curves are an important tool in mapping the distribution of mass in a galaxy. The velocity increases rapidly with distance from the center of the galaxy, and then remains approximately constant, even in the outermost parts of the visible galaxy. This implies that the mass is not centrally concentrated, as might be expected, but is distributed into a dark halo extending up to five times the radius of the optical disk. The rotation velocities are measured from the Doppler shift in stellar absorption lines or the emission line spectra of H II regions in the plane of the galaxy. Neutral hydrogen extends farther than the luminous matter of a galactic disk and radio observations can trace out the rotation curve to radii of tens of kiloparsecs.

References in periodicals archive ?
They found one form of [mu]x) for which very little DM was required, but this form was found to be unrealistic, when rotation curve data was taken into account.
Context only carries you so far, and at some point you may find your mind spinning as someone asks, "So, what's with the galaxy's rotation curve lately?"
The agreement with the observed rotation curve is striking: the calculations even reproduce a hitherto unexplained "kink" in the curve 35,000 light-years from the center.
Another motivation for the new dust-penetrated classification scheme is that it is related to the kinematics or dynamics of a galaxy, factors that are best understood by analyzing a galaxy's rotation curve. Rotation curves are plots of the velocities at which stars (or gas) orbit the center of a galaxy at different distances from its nucleus.
As Greenhill's team cautions in the Astrophysical Journal Letters for November 20, 1996, the galaxy's innermost "rotation curve" doesn't quite follow Kepler's law as expected from a singular black hole that outweighs its surroundings.
They then used the resulting rotation curve to "weigh" the material within about 40,000 light-years of the Milky Way's core.
Additionally, the galaxy components were not added one by one, instead of this, we derived a generalized Miyamoto-Nagai model that can be adjusted very accurately to fit the observed rotation curve and hence it is assumed that all (or most of) the components are taken into account.
Currently one of the best tools available to analyze the material content of a spiral galaxy is the rotation curve (Binney & Tremaine, 2008; Leblanc, 2010; Rubin et al.
Upon finishing her observations, Rubin's galactic rotation curve extended about five times farther than it had in the early 1960s--and it was still flat.
In fact rotation curve results for such galaxies exhibit precisely this behaviour (see, e.g., discussion in [554] in the context of conformal Weyl gravity): that is, the rotation curves of these galaxies start rising immediately.
Modeling the Newtonian dynamics for rotation curve analysis of thin-disk galaxies.
Difference in the external rotation curve was induced by the swing of ipsilateral leg in walking posture.