%0 Generic %1 jethwa2016upper %A Jethwa, Prashin %A Belokurov, Vasily %A Erkal, Denis %D 2016 %K dark halo low mass matter %T The upper bound on the lowest mass halo %U http://arxiv.org/abs/1612.07834 %X We explore the connection between galaxies and dark matter halos in the Milky Way (MW) and quantify the implications on properties of the dark matter particle and the phenomenology of low-mass galaxy formation. This is done through a probabilistic comparison of the luminosity function of MW dwarf satellite galaxies to models based on two suites of zoom-in simulations. One suite is dark-matter-only while the other includes a disk component, therefore we can quantify the effect of the MW's baryonic disk on our results. We apply numerous Stellar-Mass-Halo-Mass (SMHM) relations allowing for multiple complexities: scatter, a characteristic break scale, and subhalos which host no galaxy. In contrast to previous works we push the model/data comparison to the faintest dwarfs by modeling observational incompleteness, allowing us to draw three new conclusions. Firstly, we constrain the SMHM relation for $10^2<M_*/M_ødot<10^8$ galaxies, allowing us to bound the peak halo mass of the faintest MW satellite to $M_vir<2.4\times10^8M_ødot$ ($1\sigma$). Secondly, by translating to a Warm Dark Matter (WDM) cosmology, we bound the thermal relic mass $m_WDM>2.9$ keV at 95% confidence, on a par with recent constraints from the Lyman-$\alpha$ forest. Lastly, we find that the observed number of ultra-faint MW dwarfs is in tension with the theoretical prediction that reionisation prevents galaxy formation in almost all $10^8M_ødot$ halos. This can be tested with the next generation of deep imaging surveys. To this end, we predict the likely number of detectable satellite galaxies in the Subaru/HSC survey and the LSST. Confronting these predictions with future observations will be amongst our strongest tests of WDM and the effect reionisation on low-mass systems.

@misc{jethwa2016upper, abstract = {We explore the connection between galaxies and dark matter halos in the Milky Way (MW) and quantify the implications on properties of the dark matter particle and the phenomenology of low-mass galaxy formation. This is done through a probabilistic comparison of the luminosity function of MW dwarf satellite galaxies to models based on two suites of zoom-in simulations. One suite is dark-matter-only while the other includes a disk component, therefore we can quantify the effect of the MW's baryonic disk on our results. We apply numerous Stellar-Mass-Halo-Mass (SMHM) relations allowing for multiple complexities: scatter, a characteristic break scale, and subhalos which host no galaxy. In contrast to previous works we push the model/data comparison to the faintest dwarfs by modeling observational incompleteness, allowing us to draw three new conclusions. Firstly, we constrain the SMHM relation for $10^2<M_*/M_\odot<10^8$ galaxies, allowing us to bound the peak halo mass of the faintest MW satellite to $M_\mathrm{vir}<2.4\times10^8M_\odot$ ($1\sigma$). Secondly, by translating to a Warm Dark Matter (WDM) cosmology, we bound the thermal relic mass $m_\mathrm{WDM}>2.9$ keV at 95% confidence, on a par with recent constraints from the Lyman-$\alpha$ forest. Lastly, we find that the observed number of ultra-faint MW dwarfs is in tension with the theoretical prediction that reionisation prevents galaxy formation in almost all $10^8M_\odot$ halos. This can be tested with the next generation of deep imaging surveys. To this end, we predict the likely number of detectable satellite galaxies in the Subaru/HSC survey and the LSST. Confronting these predictions with future observations will be amongst our strongest tests of WDM and the effect reionisation on low-mass systems.}, added-at = {2016-12-26T17:40:58.000+0100}, author = {Jethwa, Prashin and Belokurov, Vasily and Erkal, Denis}, biburl = {https://www.bibsonomy.org/bibtex/236734ab9ec9fb6b61e9a05ae4787c808/miki}, description = {[1612.07834] The upper bound on the lowest mass halo}, interhash = {b1cec042c28523024ff6e6ff813b77ed}, intrahash = {36734ab9ec9fb6b61e9a05ae4787c808}, keywords = {dark halo low mass matter}, note = {cite arxiv:1612.07834Comment: 25 pages, 14 figures. Submitted to MNRAS, comments welcome}, timestamp = {2016-12-26T17:40:58.000+0100}, title = {The upper bound on the lowest mass halo}, url = {http://arxiv.org/abs/1612.07834}, year = 2016 }