Stellar mass - to - light ratio gradients in galaxies : correlations with mass

We analyse the stellar mass-to-light ratio (M/L) gradients in a large sample of local galaxies taken from the Sloan Digital Sky Survey, spanning a wide range of stellar masses and morphological types. As suggested by the well-known relationship between M/L values and colours, we show that M/L gradients are strongly correlated with colour gradients, which we trace to the effects of age variations. Stellar M/L gradients generally follow patterns of variation with stellar mass and galaxy type that were previously found for colour and metallicity gradients. In late-type galaxies M/L gradients are negative, steepening with increasing mass. In early-type galaxies M/L gradients are shallower, while presenting a twofold trend: they decrease with mass up to a characteristic mass of ? and increase at larger masses. We compare our findings with other analyses and discuss some implications for galaxy formation and for dark matter estimates. DOI: https://doi.org/10.1111/j.1365-2966.2011.19438.x Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-55361 Accepted Version Originally published at: Tortora, C; Napolitano, N R; Romanowsky, A J; Jetzer, P; Cardone, V F; Capaccioli, M (2011). Stellar mass-to-light ratio gradients in galaxies: correlations with mass. Monthly Notices of the Royal Astronomical Society, 418(3):1557-1564. DOI: https://doi.org/10.1111/j.1365-2966.2011.19438.x ar X iv :1 10 7. 29 18 v1 [ as tr oph .C O ] 1 4 Ju l 2 01 1 Mon. Not. R. Astron. Soc. 000, 1–?? (xxxx) Printed 18 July 2011 (MN LTEX style file v2.2) Stellar mass-to-light ratio gradients in galaxies: correlations with mass. C. Tortora, N.R. Napolitano, A.J. Romanowsky, Ph. Jetzer, V.F. Cardone M. Capaccioli 1 Universität Zürich, Institut für Theoretische Physik, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland 2 INAF – Osservatorio Astronomico di Capodimonte, Salita Moiariello, 16, 80131 Napoli, Italy 3 UCO/Lick Observatory, University of California, Santa Cruz, CA 95064, USA 4 INAF Osservatorio Astronomico di Roma via di Frascati, 33, 00040 Monte Porzio Catone (Roma), Italy 5 Dipartimento di Scienze Fisiche, Università di Napoli Federico II, Compl. Univ. Monte S. Angelo, 80126 Napoli, Italy