3D map of space dust video: galactic selfie of the Milky Way

A 3D map of space dust in the Milky Way providing insight into the galaxy's structure.

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Space dust is beautiful. See for yourself in the video above, which takes you on a voyage through the ghostly wisps of dust strewn across the Milky Way. These images are part of a three-dimensional map of the galaxy’s dust – the largest map of its kind, covering three-quarters of the sky.

The map will help us better envision what the Milky Way looks like, says Gregory Green of Harvard University in Cambridge, Massachusetts, who led the mapping effort. While we have plenty of ideas about our home galaxy’s structure, it’s hard to know for sure – we can’t send a telescope outside the galaxy to take a cosmic selfie.

But by knowing how the dust is distributed, astronomers can more accurately piece together the galaxy’s structure, how its spiral arms are shaped, whether it has a bar across it or how thick the galaxy’s disc is.

Sunset stars
The map can also illuminate the birth of stars. For example, Green says, it reveals distinct bubble shapes surrounding Orion A and Orion B, two clouds that are part of the famous Orion nebula. The bubbles form around existing stars which blow a wind of particles out into space. These shove surrounding gas and dust into a hollow sphere and create a shell of denser material that can then form new stars.

Astronomers used data collected by the Pan-STARRS telescope in Hawaii to build the map.
'We present a three-dimensional map of interstellar dust reddening, covering three-quarters of the sky out to a distance of several kiloparsecs, based on Pan-STARRS 1 and 2MASS photometry,' said the researchers in their paper, due to be published in the Astrophysical Journal.
'The map reveals a wealth of detailed structure, from filaments to large cloud complexes.
'We expect the three-dimensional reddening map presented here to find a wide range of uses, among them correcting for reddening and extinction for objects embedded in the plane of the Galaxy, studies of Galactic structure, calibration of future emission-based dust maps and determining distances to objects of known reddening.'

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arxiv.org...

We present a three-dimensional map of interstellar dust reddening, covering three-quarters of the sky out to a distance of several kiloparsecs, based on Pan-STARRS 1 and 2MASS photometry. The map reveals a wealth of detailed structure, from filaments to large cloud complexes. The map has a hybrid angular resolution, with most of the map at an angular resolution of 3.4' to 13.7', and a maximum distance resolution of ~25%. The three-dimensional distribution of dust is determined in a fully probabilistic framework, yielding the uncertainty in the reddening distribution along each line of sight, as well as stellar distances, reddenings and classifications for 800 million stars detected by Pan-STARRS 1. We demonstrate the consistency of our reddening estimates with those of two-dimensional emission-based maps of dust reddening. In particular, we find agreement with the Planck 353 GHz optical depth-based reddening map to within 0.05 mag in E(B-V) to a depth of 0.5 mag, and explore systematics at reddenings less than E(B-V) ~ 0.08 mag. We validate our per-star reddening estimates by comparison with reddening estimates for stars with both SDSS photometry and SEGUE spectral classifications, finding per-star agreement to within 0.1 mag out to a stellar E(B-V) of 1 mag. We compare our map to two existing three-dimensional dust maps, by Marshall et al. (2006) and Lallement et al. (2013), demonstrating our finer angular resolution, and better distance resolution compared to the former within ~3 kpc. The map can be queried or downloaded at this http URL We expect the three-dimensional reddening map presented here to find a wide range of uses, among them correcting for reddening and extinction for objects embedded in the plane of the Galaxy, studies of Galactic structure, calibration of future emission-based dust maps and determining distances to objects of known reddening.

If the light switch turned on and all of space lit up it would look like sand.