Impacts of dark energy on weighing neutrinos after Planck 2015

We investigate how dark energy properties impact the cosmological limits on the total mass of active neutrinos. We consider two typical, simple dark energy models (that have only one more additional parameter than [Lambda]CDM ), i.e., the sub(w) CDM model and the holographic dark energy (HDE) model, as examples, to make an analysis. In the cosmological fits, we use the Planck 2015 temperature and polarization data, in combination with other low-redshift observations, including the baryon acoustic oscillations, type Ia supernovae, and Hubble constant measurement, as well as the Planck lensing measurements. We find that, once dynamical dark energy is considered, the degeneracy between [Sigma]m sub([nu]) and H 0 will be changed, i.e., in the [Lambda]CDM model, [Sigma]m sub([nu]) is anticorrelated with H sub(0), but in the wCDM and HDE models, [Sigma]m sub([nu]) becomes positively correlated with H 0 . Compared to [Lambda]CDM , in the wCDM model the limit on [Sigma]m [nu] becomes much looser, but in the HDE model the limit becomes much tighter. In the HDE model, we obtain [Sigma]m sub([nu])