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The Gaia map of the Milky Way reveals a pair of triangular features at nearlysymmetric locations on opposite sides of the Galactic Center. In this paper weexplore the implications of these features assuming they are manifestations ofa caustic ring in the dark matter distribution of the Milky Way halo. Theexistence of a series of such rings is predicted by the Caustic Ring Model. Themodel's phase-space distribution is that acquired by a rethermalizingBose-Einstein condensate of axions or axion-like particles. We show that dustis gravitationally entrained by cold axion flows and propose this as anexplanation for the sharpness of the triangular features. The locations of thefeatures imply that we on Earth are much closer to the fifth caustic ring thanthought on the basis of pre-Gaia observations. Most likely we are inside itstricusp cross-section. In that case the dark matter density on Earth isdominated by four cold flows, termed Big, Little, Up and Down. If we areoutside the tricusp cross-section the dark matter density on Earth is dominatedby two cold flows, Big and Little. We use the triangular features in the Gaiamap, and a matching feature in the IRAS map, to estimate the velocity vectorsand densities of the four locally dominant flows.

Implications of triangular features in the Gaia skymap for the Caustic Ring Model of the Milky Way halo