Arp 84 - Heron Galaxies in Canes Venatici

Arp 84, better known as the “Heron Galaxies”, is a close interacting pair in the constellation Canes Venatici, composed of NGC 5394 and NGC 5395, lying at a distance of roughly 160 million light-years. Arp noted that NGC 5495 is a spiral with a high surface luminosity companion at the end of one of its arms. The nickname comes from the pair’s visual resemblance to a long-necked bird: NGC 5395 forms the larger “body,” while the distorted disk of NGC 5394 appears like a head and beak poised at the edge of the interaction.

This system is a textbook example of a strong tidal encounter between two spiral galaxies. NGC 5395 shows a broad, asymmetrical disk with stretched spiral arms and enhanced star formation along regions compressed by gravitational forces. Its smaller companion, NGC 5394, has been far more dramatically affected—its structure is heavily distorted, and observations across the spectrum reveal intense, localized starburst activity likely triggered as gas was funneled inward during the close pass. Although the galaxies have not yet merged, their shapes clearly record the violence of repeated encounters.

What makes Arp 84 particularly engaging is that it captures interaction at a stage where both galaxies are still recognizable as spirals, yet clearly transformed. Long tidal features, uneven arm brightness, and subtle plumes around the pair hint at material being exchanged or stripped away, slowly building the extended halos that will persist long after the visible disks settle into a new configuration.

This image is based on just 2 hours of LRGB integration captured with Telescope Live’s SPA-2-CCD system.