Abstract
Context. The Vela complex is a region of the sky that gathers several stellar and interstellar structures in a few hundred square degrees. Aims.Gaia data now allow us to obtain a 3D view of the Vela interstellar structures through the dust extinction. Methods. 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 to this cube to locate clumps and dense structures. Results. We analysed 18 million stars over 450 deg2 to obtain the extinction density of the Vela complex from 0.5 to 8 kpc at ℓ ∈ [250° ,280° ] and b ∈ [ − 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 of three substructures instead of four, as suggested by the 2D densities. These substructures form the shell of a large cavity. This cavity is visually aligned with the Vela supernova remnant but located at a greater distance. We provide a catalogue of location, distance, size, and total dust content of Interstellar Medium (ISM).
Highlights
A large number of structures are known towards the Vela constellation
While the overall shape of the Vela Molecular Ridge (VMR) is quite similar to the IRAS view shown in Fig. 1, it differs in the details, as the strongest emissions at 60 μm do not coincide with the areas with the strongest cumulative extinction
Clump 6 presents a relatively high extinction density and reasonable apparent angle, but it is barely visible in the column view (Fig. 2) because it is overlapped by VMR D
Summary
The IRAS Vela shell (hereafter IVS) is a ring shell first noticed in IRAS data by Sahu (1992) It is centred at ( , b) = (263◦, −7◦) at the distance of 450 pc (Pettersson 2008). Franco (2012) analysed the interstellar reddening in six distinct areas using photometry to study the largest structures of the Vela complex, but not the densest parts of the complex. Hottier et al (2020) analysed 2MASS and Gaia DR2 data with the FEDReD algorithm (Babusiaux et al 2020) and derived the extinction density in the Galactic plane. In a previous work (Hottier et al 2020), we noticed that the Vela complex presents large structures that reach distances up to 5 kpc. For the astrometric information (Lindegren et al 2018), we used Eq (1) of Arenou et al (2018), we corrected the parallax zero point of −0.03 mas, and we did not use the parallax when + 3 × σ < 0 to remove spurious astrometric solutions
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