NGC 5395 & NGC 5394
The Heron Galaxy

The gravitationally interacting galaxy pair Arp 84 in the constellation Canes Venatici consists of the two spiral galaxies NGC 5395 and NGC 5394, which are also known as the Heron Galaxy due to their characteristic silhouette. According to astrophysical measurements, its distance to Earth is approximately 160 to 165 million light-years. While the larger main galaxy NGC 5395 forms the "body" of the heron and has an intrinsic diameter of about 140,000 light-years, the smaller companion galaxy NGC 5394 – the "head" – has a diameter of around 90,000 light-years.

The horizontally aligned overview image clearly shows the geometric arrangement of the objects in space, using the rotated main axis of the pair as a direct orientation reference (the direction toward the heron's head points north, placing North to the right of the image):

• NGC 5395 (Body Galaxy): Located slightly to the top-left of the image field, it appears to the observer in a nearly face-on view (viewed from above).
• NGC 5394 (Head Galaxy): Positioned diagonally below, slightly offset downward and to the right, extending its elongated tidal arms in a helical fashion into space.

The morphology of the system bears witness to a high-energy past, as the smaller NGC 5394 has already completely punched through the dense disk of the larger NGC 5395 at least once during an earlier phase of their passage. This gravitational direct hit massively compressed the interstellar gas in both systems and triggered widespread star-forming regions (starbursts), which appear in exposures as bright, bluish knots along the distorted spiral arms.

Extremely distant background galaxies, which share no physical relationship with Arp 84, reveal themselves in the image background of the chosen narrow crop. Located directly at the tip of the northern tidal arm of NGC 5394 is the edge-on aligned galaxy PGC 2101092, often described as the "fish in the heron's beak," which is around 640 to 670 million light-years away. Above the head, further to the north, lies the lenticular galaxy PGC 49759 (IC 4356) at a distance of about 680 to 700 million light-years. In the immediate vicinity of this object, the two faint background systems PGC 2102129 and PGC 2102430 round out this distant cosmic deep-field scenario.