http://arxiv.org/abs/2003.01125
Studies of flux anomalies statistics and perturbations in stellar streams have the potential to constrain models of warm dark matter (WDM), including sterile neutrinos. Producing these constraints requires a parametrization of the WDM mass function relative to that of the cold dark matter (CDM) equivalent. We use five WDM models with half-mode masses, $M_\mathrm{hm}=[1.3,35]\times10^{8}$~$M_{\odot}$, spread across simulations of the Local Group, lensing ellipticals and the $z=2$ universe, to generate such a parametrization: we fit parameters to the functional form $n_\mathrm{WDM}/n_\mathrm{CDM}=(1+(\alpha M_\mathrm{hm}/M_{X})^{\beta})^{\gamma}$. For $M_{X}\equiv$ virial mass of central halos we obtain $\alpha=2.3$, $\beta=0.8$, and $\gamma=-1.0$, and this fit is steeper than the EPS formalism predicts. For $M_{X}\equiv$ mass of subhalos we instead obtain $\alpha=4.2$, $\beta=2.5$ and $\gamma=-0.2$; in both mass definitions the scatter is $\sim20$ percent. However, we caution that robust constraints will require bespoke simulations and a careful definition of halo mass, particularly for subhalos of mass $<10^{8}M_{\odot}$.
M. Lovell
Wed, 4 Mar 20
16/51
Comments: 5 pages, 2 figures. To be submitted to ApJL. Contact: lovell@hi.is
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