Scientists at the Max Planck Institute for Extraterrestrial Physics in Germany have produced the first detailed three-dimensional map of the stars that form the inner regions of our Milky Way, the nuclear bulge (see p. 389).
Using publicly available data from ESO’s VISTA survey telescope in Chile, the team found a peanut-shaped bulge with an elongated bar and a prominent X-structure, which had been hinted at in previous studies. This indicates that the Milky Way was originally a pure disk of stars, which then formed a thin bar, before buckling into the boxy peanut shape seen today.
The scientists expect that this measurement of the three-dimensional density of the bulge will help to constrain galaxy evolution models for both our Milky Way and spiral galaxies in general. It will also support a number of further studies on different stellar populations, gas flows, or microlensing.
Read the MPE press release and the ESO press release for more images and a movie simulation of the bulge rotating. The research is published as “Mapping the three-dimensional density of the Galactic bulge with VVV red clump stars” by C. Wegg et al. in the Monthly Notices of the Royal Astronomical Society.