FEDReD III: Unraveling the 3D structure of Vela

Gaia data now allows us to obtain a 3D view of the Vela interstellar structures through the dust extinction. We used the FEDReD (Field Extinction-Distance Relation Deconvolver) algorithm on near-infrared 2MASS data, cross-matched with the Gaia DR2 catalogue, to obtain a 3D cube of extinction density.

We applied the FellWalker algorithm on this cube to locate clumps and dense structures. We analysed 18 million stars on 450 deg 2 to obtain the extinction density of the Vela complex from 0.5 to 8kpc at l in [250, 280] and b in [-10, 5].This cube reveals the complete morphology of known structures and relations between them. In particular, we show that the Vela Molecular Ridge is more likely composed by three substructures instead of four, as suggested by the 2D densities.