Featured Image: Warped, Flared, and Ultra-thin

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.


“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