\bf The Infrared D -- $\sigma$ Relation of Elliptical Galaxies

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Session 52 -- Elliptical Galaxies
Display presentation, Tuesday, 10, 1995, 9:20am - 6:30pm

[52.17] \bf The Infrared D -- $\sigma$ Relation of Elliptical Galaxies

M.~Gregg (IGPP, Lawrence Livermore National Laboratory)

A popular method for estimating distances to elliptical galaxies relies on the correlation between diameter and the central velocity dispersion. The diameters are usually defined as the size of a circular aperture within which an elliptical has a certain surface brightness, 20.75mag/sq.arcsec in B or 19.80 in V, the two most commonly used bands. The scatter in the D--$\sigma$ relation of the Coma cluster is reduced by a factor of $\sim1.5-2$ if near infrared photometry is used instead. This improvement is comparable to that of B band D--$\sigma$ over the Faber-Jackson relation (B$_{\rm T}~ {\em vs}.\ \sigma$) and represents a further increase in the accuracy of estimated distances.

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