science & techESA/Hubble

A galaxy seen edge-on shows a bulge that bulges far above and below its disc

the gist

Hubble's image shows the spiral galaxy UGC 10043, about 150 million light-years away in the constellation Serpens, seen directly from the side. Its disc appears as a thin line cut by a thick dust lane, while a glowing, egg-shaped central bulge rises well above and below the disc. The bulge is unusually large, possibly because the galaxy has been drawing gas from a nearby dwarf galaxy, which may also explain why its disc is warped. The picture is a composite of two sets of Hubble data taken 23 years apart, in 2000 and 2023. Such side-on views reveal structures that are usually hidden in face-on pictures.

so what

Seeing galaxies edge-on exposes the vertical structure of a galaxy that face-on views hide. The 23-year gap between datasets also shows how long-running telescope archives keep becoming more useful.

ESA/Hubble · CC BY 4.0

Image: ESA/Hubble & NASA, R. Windhorst, W. Keel