The Edge of a Spiral

Day 22 of the 2024 Space Telescope Advent Calendar: the edge of a spiral. Located roughly 150 million light-years from Earth in the constellation Serpens, UGC 10043 is one of the somewhat rare spiral galaxies that are seen edge-on. From this point of view, we see the galaxy’s disk as a sharp line through space, overlaid with a prominent dust lane. One can see the lights of some active star-forming regions in the arms, shining out from behind the dust. Strikingly, we can also see that the center of the galaxy sports a glowing, almost egg-shaped “bulge,” rising far above and below the disk. The unusually large size of this bulge compared with the galaxy’s disk is possibly thanks to UGC 10043 siphoning material from a nearby dwarf galaxy.

See the full advent calendar here, where a new image will be revealed each day until December 25.