Tully-Fisher relation


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Tully-Fisher relation

[¦təl·ē ′fish·ər ri‚lā·shən]
(astronomy)
A relation between the rotational velocity of a galaxy, as reflected in the width of the 21-centimeter line, and the intrinsic luminosity of the galaxy.
References in periodicals archive ?
The observed Tully-Fisher relation (Tully & Fisher 1977) shows that for spiral galaxies [v.
3 shows a comparison of observations and predictions of MOND regarding the Tully-Fisher relation.
Even more surprising, all disk galaxies seem to share the same relationship between their luminosity and the speed with which their disk rotates (known as the Tully-Fisher relation, after its first proponents), regardless of their surface brightness.
The results explain the large disks and slow inner rotation of low-surface-brightness galaxies, and they account for the properties that these galaxies share with normal galaxies, including the Tully-Fisher relation.
This concept was fully developed in 1977 by Brent Tully and Richard Fisher and soon became known as the Tully-Fisher relation.
Although the universe was at first assumed to be expanding uniformly, the wholesale use of the Tully-Fisher relation revealed large-scale departures from uniformity.