21-cm observations and warm dark matter models. (arXiv:1904.03097v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Boyarsky_A/0/1/0/all/0/1">Alexey Boyarsky</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Iakubovskyi_D/0/1/0/all/0/1">Dmytro Iakubovskyi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ruchayskiy_O/0/1/0/all/0/1">Oleg Ruchayskiy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rudakovskyi_A/0/1/0/all/0/1">Anton Rudakovskyi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Valkenburg_W/0/1/0/all/0/1">Wessel Valkenburg</a>
Observations of the redshifted 21-cm signal (in absorption or emission) allow
us to peek into the epoch of “dark ages” and the onset of reionization. These
data can provide a novel way to learn about the nature of dark matter, in
particular about the formation of small size dark matter halos. However, the
connection between the formation of structures and 21-cm signal requires
knowledge of stellar to total mass relation, escape fraction of UV photons, and
other parameters that describe star formation and radiation at early times.
This baryonic physics depends on the properties of dark matter and in
particular in warm-dark-matter (WDM) models, star formation may follow a
completely different scenario, as compared to the cold-dark-matter case. We use
the recent measurements by the EDGES collaboration to demonstrate that when
taking the above considerations into account, the robust WDM bounds are in fact
weaker than those given by the Lyman-$alpha$ forest method and other structure
formation bounds. In particular, we show that resonantly produced 7 keV sterile
neutrino dark matter model is consistent with these data. However, a holistic
approach to modelling of the WDM universe holds great potential and may in the
future make 21-cm data our main tool to learn about dark matter clustering
properties.
Observations of the redshifted 21-cm signal (in absorption or emission) allow
us to peek into the epoch of “dark ages” and the onset of reionization. These
data can provide a novel way to learn about the nature of dark matter, in
particular about the formation of small size dark matter halos. However, the
connection between the formation of structures and 21-cm signal requires
knowledge of stellar to total mass relation, escape fraction of UV photons, and
other parameters that describe star formation and radiation at early times.
This baryonic physics depends on the properties of dark matter and in
particular in warm-dark-matter (WDM) models, star formation may follow a
completely different scenario, as compared to the cold-dark-matter case. We use
the recent measurements by the EDGES collaboration to demonstrate that when
taking the above considerations into account, the robust WDM bounds are in fact
weaker than those given by the Lyman-$alpha$ forest method and other structure
formation bounds. In particular, we show that resonantly produced 7 keV sterile
neutrino dark matter model is consistent with these data. However, a holistic
approach to modelling of the WDM universe holds great potential and may in the
future make 21-cm data our main tool to learn about dark matter clustering
properties.
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