Neutrino Torquing

We show how galaxy spin alignment directly measures the initial tidal field, thus doubling the information content of galaxy surveys. The initial density field can be recovered to $ksim 1$ using spin alignment and non-linear galaxy displacement reconstruction, separately. By measuring two scalar fields, we measure the gravitational field of cold dark matter and neutrinos. A next generation 21cm survey can achieve the required sensitivity to measure the contribution of primordial neutrinos to galaxy spin.

Speaker: Ue-Li Pen, CITA