Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/43952

Title

Dependence of the Fundamental Plane scatter on galaxy age

Author(s)

Forbes, Duncan A.;  Ponman, Trevor J.;  Brown, Richard J. N.

Abstract

The fundamental plane (FP) has an intrinsic scatter that cannot be explained purely by observational errors. Using the recently available age estimates for nearby early-type galaxies, we show that a galaxy's position relative to the FP depends on its age. In particular, the mean FP corresponds to elliptical galaxies with an age of 10 Gyr. Younger galaxies are systematically brighter, with a higher surface brightness relative to the mean relation. Old elliptical galaxies form an 'upper envelope' to the FP. For our sample of mostly noncluster galaxies, age can account for almost half of the scatter in the B-band FP. Distance determinations based on the FP may have a systematic bias, if the mean age of the sample varies with redshift. We also show that fundamental plane residuals, colors, and Mg2 line strength are consistent with an ageing central burst superposed on an old stellar population. This reinforces the view that these age estimates are tracing the last major episode of star formation induced by a gaseous merger event. We briefly discuss the empirical 'evolutionary tracks' of merger remnants and young elliptical galaxies in terms of their key observational parameters.

Publication type

Journal article

Source

Astrophysical Journal Letters, Vol. 508, no. 1 (Nov 1998), pp. L43-L46

Publication year

1998

Keyword(s)

cD;  Elliptical galaxies;  FP;  Fundamental parameters;  Fundamental Plane;  Galaxy evolution;  Kinematics and dynamics;  Lenticular galaxies;  Photometry

Publisher

University of Chicago Press

ISSN

0004-637X

Publisher URL

http://dx.doi.org/10.1086/311715

Copyright

Copyright © 1998 The American Astronomical Society. All rights reserved.

Peer reviewed