Sentences with phrase «velocity dispersion»
"Velocity dispersion" refers to the degree of variation or spread in the speeds or velocities of objects within a group or population. It measures how much the individual velocities differ from the average velocity. Full definition
The width of a spectral line reflects velocity dispersion of the gas and shows up due to the Doppler effect caused by a distribution of the velocities of gas molecules.
sciencedaily.com
A paper, titled «A High Stellar Velocity Dispersion and ~ 100 Globular Clusters for the Ultra Diffuse Galaxy Dragonfly 44,» describing their findings was published in the journal Astrophysical Journal Letters on Thursday.
«If you really want to have a precise mass measurement of the black hole in a specific galaxy, you'd better use the slightly more cumbersome velocity dispersion method,» Ferrarese says.
Stars from those galaxies can also accrete onto the disk, but accretion alone can not account for the observed increase in velocity dispersion with stellar age, Dorman said.
[19] The members of this cluster are orbiting the center of mass with a peak velocity dispersion of 7.9 km s − 1.
The galaxy formed 11 billion years ago, and its star - forming gas has one of the highest ionized gas velocity dispersions ever measured.
The disk galaxy properties like total mass and central velocity dispersion also lie within a much narrower range than the black hole masses.
SDSS image of an example MaNGA target galaxy (left), with some of the many things we can learn about it shown in the right and bottom panels: stellar velocity dispersion, stellar mean velocity, stellar population age, metallicity, etc. [Blanton et al. 2017]
The new method will be invaluable for statistical studies of large numbers of galaxies, says Laura Ferrarese of Rutgers University in Piscataway, New Jersey, co-discoverer of the velocity dispersion correlation.
Now, a team led by Alister Graham of the Astrophysics Institute of the Canary Islands has taken the velocity dispersion approach one step further.
Velocity dispersion is a statistical measure of the range of velocities of all stars in a galaxy, easily obtainable with a spectrograph.
An easier approach was developed 2 years ago, after astronomers found a strong correlation between a black hole's mass and the velocity dispersion of its host galaxy.
The team accounted for this, and was able to show that the velocity dispersion or random motion of the RR Lyrae star population was very high relative to the other stars in the Milky Way's center.
The study presents the velocity dispersion of young, intermediate - age, and old stars in the disk of Andromeda, the first such measurement in another galaxy.
For the inner few kiloparsecs of the elliptical galaxies, the velocity dispersion = 220 × (L / L *) 0.25, where L * is a characteristic galaxy luminosity (around 10 billion solar luminosities).
The elliptical galaxy's mass = k × (velocity dispersion) 2 × (the distance the stars are from the galaxy center) / G, where k is a factor that depends on the shape of the galaxy and the angle the galaxy is from Earth.
An elliptical galaxy's luminosity can be found from the velocity dispersion of the stars in the central few kiloparsecs of the galaxy.
Sandra Faber and Robert Jackson discovered in 1976 a simple relation between the spread of velocities (called the velocity dispersion) and the luminosity of elliptical galaxies.
«The really important piece of evidence was the measurement of velocity dispersion.
Muriel, H., H. Quintana, L. Infante, D.G. Lambas, and M.J. Way, 2002: Velocity dispersions and cluster properties in the Southern Abell Redshift Survey Clusters.