A Grand Design of Imperfections

With its swirling arms and luminous core, NGC 5364 is unmistakably a spiral galaxy, lying in the constellation Virgo. But it’s not just any spiral galaxy imaged by the Dark Energy Camera (DECam) on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. This eye-catching stellar body is classified as a grand design spiral galaxy. Grand design spiral galaxies are characterized by prominent, well-defined arms that circle outwards from a distinct core. Only ten percent of spiral galaxies are given this descriptive name and they are considered the archetype of spiral galaxies owing to their ‘perfect’ structure. However, NGC 5364 is not as perfect as it may appear. Compared to other grand design spirals, its arms are actually amorphous and asymmetrical. This distortion is thought to be due to interactions with the nearby lenticular galaxy NGC 5363, which can be seen in this image as a fuzzy smear below NGC 5364. Despite its significantly smaller size, the close proximity of this galaxy to NGC 5364 results in a mutual tugging. This moves around the stars and gas within NGC 5364’s arms and warps the overall shape of the galaxy.