Abstract
By means of a semi-analytic model of galaxy formation, we show how the local observed relation between age and galactic stellar mass is affected by assuming a dark matter power spectrum with a small-scale cut-off. We compare results obtained by means of both a Λ cold dark matter (ΛCDM) and a Λ warm dark matter (ΛWDM) power spectrum - suppressed with respect to the ΛCDM at scales below ~1 Mpc. We show that, within a ΛWDM cosmology with a thermal relic particle mass of 0.75 keV, both the mass-weighted and the luminosity-weighted age-mass relations are steeper than those obtained within a ΛCDM universe, in better agreement with the observed relations. Moreover, both the observed differential and cumulative age distributions are better reproduced within a ΛWDM cosmology. In such a scenario, star formation appears globally delayed with respect to the ΛCDM, in particular in low-mass galaxies. The difficulty of obtaining a full agreement between model results and observations is to be ascribed to our present poor understanding of baryonic physics.
| Original language | English |
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| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 440 |
| Issue number | 3 |
| Pages (from-to) | 2066-2076 |
| ISSN | 0035-8711 |
| DOIs | |
| Publication status | Published - 1 May 2014 |