Three-dimensional dust density structure of the Orion, Cygnus X, Taurus, and Perseus star-forming regions

T. E. Dharmawardena, C. A. L. Bailer-Jones, M. Fouesneau, D. Foreman-Mackey

Abstract: Interstellar dust affects many astronomical observations through absorption and reddening, yet this extinction is also a powerful tool for studying interstellar matter in galaxies. Three-dimensional reconstructions of dust extinction and density in the Milky Way have suffered from artefacts such as the fingers-of-god effect and negative densities, and have been limited by large computational costs. Here we aim to overcome these issues with a novel algorithm that derives the three-dimensional (3D) extinction density of dust in the Milky Way using a latent variable Gaussian Process in combination with variational inference. Our model maintains non-negative density and hence monotonically non-decreasing extinction along all lines-of-sight, while performing the inference within a reasonable computational time.

Figure 5: Top:Simulated Density map sampled at the indicated distances; Middle:Our model reconstructed Density map sampled at the same distances as the simulated map; Bottom:Residual of Model Predicted density - Simulated Density

Figure 24: As Fig. 23, showing Planck Dust Intensity.

Figure 23: Top four panels: Planck 850 μm maps for Orion (top left), Cygnus X (top right), Perseus (upper middle left), Taurus (upper middle right); Bottom four panels: Ratio of total extinction predicted by our model to Planck 850 μm normalised by the median of the ratio. Predicted extinction contours overlaid. Ratio plots are arranged in the same pattern as the Planck emission maps.