NGC 5474

NGC 5474 is an asymmetric spiral galaxy and it is being dramatically disturbed by its much larger neighbor M101. With respect to this image, M101 is several fields away towards the upper left direction. At first glance, it might appear that M101 is somehow gravitationally dragging the nucleus right out of NGC 5474. However, astronomers that model these kinds of galactic interactions on a computer find a slightly different story. When using tens (if not hundreds) of thousands of point masses for stars, astronomers found that the asymmetry displayed in NGC 5474 is probably relatively short lived. We just happen to be looking at this galaxy in a state of "sloshed" agitation. As NGC 5474 orbits M101, the amount of asymmetry depends of the relationship between the direction of orbital revolution about M101 and the sense of rotation for NGC 5474ʼs disk. If the revolution is opposite that of disk rotation, as it is in the case of NGC 5474, then the lopsided state can survive for many galactic rotations after an initial (strong) tidal perturbation.Note that the seemingly grainy appearance of this galaxy is due to partially resolving some of the brighter stars in the disk. A healthy sprinkling of pink star forming regions, and blue (young) stellar associations can also be seen along the spiral structure of the galaxy.

This image was taken as part of Advanced Observing Program (AOP) program at Kitt Peak Visitor Center during 2014.