科研之友
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摘要
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 Lambda cold dark matter (Lambda CDM) and a Lambda warm dark matter (Lambda WDM) power spectrum - suppressed with respect to the Lambda CDM at scales below similar to 1 Mpc. We show that, within a Lambda WDM 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 Lambda CDM universe, in better agreement with the observed relations. Moreover, both the observed differential and cumulative age distributions are better reproduced within a Lambda WDM cosmology. In such a scenario, star formation appears globally delayed with respect to the Lambda CDM, 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.
- 出版日期2014-5
