galactic rotation

galactic rotation

The rotation of the Galaxy about its center, all its components sharing in this rotation to varying degrees. The predominant motion in the galactic disk is circular and parallel to the galactic plane. The orbital speed is determined by the mass within a star's orbit, not by the Galaxy's total mass, so the stars' rotation speeds do not follow Kepler's laws. The rotation speed increases from near zero to 150 km s–1 in the first kiloparsec of the Galaxy's radius, then increases more gradually to a peak near the Sun's orbit (at a radius of about 10 kpc). Farther away it may fall off gradually or remain roughly constant. The rotation velocity of the local standard of rest in the galactic plane was formerly taken to be 250 km s–1, but the accepted value is now 220 km s–1 as a result of the Galaxy's massive dark halo. Objects in the galactic halo display much more random motions than those in the disk and the system as a whole has only a small residual rotation with respect to the galactic center. See also rotation curve.

galactic rotation

[gə′lak·tik rō′tā·shən]
(astronomy)
The rotation of the Milky Way about an axis through the center and perpendicular to the plane of the Galaxy; the rotation is apparent from the highly flattened shape and from relative stellar motion.
References in periodicals archive ?
On the other hand, the linear term (for [gamma] > 0) could help in explaining the inferred flatness of galactic rotation curves, which has been interpreted as one of the key evidences for the presence of dark matter.
In addition to the regular Galactic rotation the scientists found the Milky Way moving perpendicular to the Galactic plane.
Part of the evidence for dark matter comes from measurements of galactic rotation: the rotation speeds indicate there is more matter in galaxies than is observed.
Sixth place went to David Rosengarten, 18, of Great Neck, N.Y., for his model of galactic rotation in the fifth dimension.
In brane-world and f(R)-gravity models, the galactic rotation curves could be explained without DM ([13-16]).
the elliptical shape of the cluster is a consequence of a rotation considerably greater than galactic rotation. This latter result disposes of the view that the elliptical shape is a consequence of galactic tidal forces."'
Washington, October 6 ( ANI ): The distance from the solar system to the galactic center is approximately 26,100 light-years, and the galactic rotation velocity in the solar system (V0) is approximately 240 km/s.
With the advent of new observational techniques, we can see the emergence of interesting new cosmological paradigms, from which the CDM seems to fit the best cosmological observations, indicating that the present day Energy Cosmologies Universe is dominated by two mysterious components, dark energy and dark matter, with the former responsible for the accelerated expansion of the Universe, while the latter is required by the strange behavior of the galactic rotation curves.
This is the direction of galactic rotation; the stars in the Sun's neighborhood are heading toward Deneb as they orbit the galaxy's center.
To explain the apparent pattern, scientists have invoked cyclic meteor showers, galactic rotation and other periodic events.
Ray, "Galactic rotation curves and brane-world models," Monthly Notices of the Royal Astronomical Society, vol.
But the Rho Ophiuchi complex is between us and the galactic interior, and Deneb is ahead of us (in terms of galactic rotation).