Though the ultra-thin galaxy UGC 11859 looks perfectly flat in the
image above, close analysis has revealed warps and flares in its disk.
These imperfections provide clues to the galaxy’s history, as the
imprints of past gravitational interactions take billions of years to
fade from the disk’s faint outer regions. Luis Ossa-Fuentes
(University of Valparaíso and Valencian International University) and
collaborators observed UGC 11859 with the 10.4-meter Gran Telescopio
Canarias, aiming to study the galaxy’s structure. They found that the
galaxy’s brightness doesn’t decrease smoothly from its center to its
outskirts, but instead drops off suddenly about 78,000 light-years from
the center. On top of that, the left side of the galaxy is tipped
upward, and the distribution of stars flares out above and below the
plane of the galaxy toward either side. While it remains to be seen if
these features are related, it’s clear that there’s more to this galaxy
than meets the eye. To learn more about the subtle structure of UGC
11859, be sure to check out the full article linked below.
By Kerry Hensley
Citation
“Flares, Warps, Truncations, and Satellite: The Ultra-thin Galaxy UGC 11859,” Luis Ossa-Fuentes et al 2023 ApJ 951 149. doi:10.3847/1538-4357/acd54c