Cloud-cloud collision in Sgr B2

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Clik here to view.© Armijos-Abendaño et al. 2020

Sgr B2 is one of the most famous star-forming regions in the Galactic Centre. In Armijos-Abendaño et al. 2020 we report observations of a shock-tracer molecule, SiO, which show that Sgr B2 is potentially a region where clouds collided ~0.5Myr ago. This collision produced strong high-velocity shocks that ignited star formation during the early stages of the evolution, and also injected turbulence, whose supersonic nature is traced by CO and SiO emission lines. In this paper we show that the density structure and shock distribution of this region can be adequately reproduced by numerical simulations of colliding clouds.

Top panels: Maps of the number density (3D renderings) and column number density of hydrogen (2D projections along the observer’s line of sight, whose direction is indicated by a red arrow), at increasing times in the range 0 < t < 1.7 Myr. Bottom panels: observed maps of the column number density of hydrogen as inferred from our 13CO data cube assuming optically thick (bottom left panel) and optically thin regimes (bottom right panel). The red, dashed square indicates regions of the same size, 30 x 30 pc, in both simulations and observations. The collision model reproduces the turbulent structure observed in Sgr B2.

The full-time evolution can be viewed in movies available here: https://tinyurl.com/y5bc3smn

The paper is available on ArXiv: https://arxiv.org/abs/2010.02757