Age-dating the Tully-Fisher relation at moderate redshift

TL;DR

This study investigates the Tully-Fisher relation at moderate redshift by analyzing stellar populations and star formation histories in late-type galaxies, revealing correlations between galaxy properties and stellar ages.

Contribution

It introduces a phenomenological model combining population synthesis and chemical enrichment to analyze galaxy evolution at z<1, highlighting the relationship between stellar mass, star formation, and galaxy dynamics.

Findings

Massive galaxies formed early with short star formation timescales.

No significant age segregation at fixed circular speed.

Older galaxies have higher circular speeds at fixed stellar-to-dynamical mass ratio.

Abstract

We analyse the Tully-Fisher relation at moderate redshift from the point of view of the underlying stellar populations, by comparing optical and NIR photometry with a phenomenological model that combines population synthesis with a simple prescription for chemical enrichment. The sample comprises 108 late-type galaxies extracted from the FORS Deep Field (FDF) and William Herschel Deep Field (WHDF) surveys at z<1 (median redshift z=0.45). A correlation is found between stellar mass and the parameters that describe the star formation history, with massive galaxies forming their populations early (zFOR~3), with star formation timescales, tau1~4Gyr; although with very efficient chemical enrichment timescales (tau2~1Gyr). In contrast, the stellar-to-dynamical mass ratio - which, in principle, would track the efficiency of feedback in the baryonic processes driving galaxy formation - does not appear to correlate with the model parameters. On the Tully-Fisher plane, no significant age segregation is found at fixed circular speed, whereas at fixed stellar-to-dynamical mass fraction, age splits the sample, with older galaxies having faster circular speeds at fixed Ms/Mdyn. Although our model does not introduce any prior constraint on dust reddening, we obtain a strong correlation between colour excess and stellar mass.