The cosmological evolution of colour gradients in spheroids

Amancio Friaca; Roberto Terlevich

doi:10.1046/j.1365-8711.2001.04435.x

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arXiv · astro-ph/0102358

The cosmological evolution of colour gradients in spheroids

Amancio Friaca·Roberto Terlevich

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Abstract

The analysis of the four-colour maps of galaxies in the Hubble Deep Field has revealed in the sample of 0.4<z<1 early-type field galaxies the existence of ellipticals with a predominantly old coeval stellar population. However, there is another, unexpected, category of HDF early-type galaxies, in which the galaxy core is significantly bluer than the outer regions. We demonstrate that these colour gradients are predicted by the multi-zone chemodynamical model for the evolution of elliptical galaxies. We suggest that the colour gradient could be used as a chronometer of the evolution of elliptical galaxies: galaxies younger than a few Gyr exhibit cores bluer than the surrounding galaxy, due to ongoing star formation, while more evolved galaxies have redder cores, due to metallicity gradients increasing towards the centre.

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Amancio Friaca, Roberto Terlevich. 2001-02-21. The cosmological evolution of colour gradients in spheroids. https://doi.org/10.1046/j.1365-8711.2001.04435.x

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