Arp269 a.k.a NGC4485/4490

About the Object

Arp 269 is a quite interesting interacting  galaxy pair consisting of NGC 4490 (aka the Cocoon Galaxy) and NGC4485. chip Arp categorized this pair as "double or multiple galaxies wrung connected arms". Nowadays, the connection is associated with a tidal bridge that forms early during the galaxy encounter. The two galaxies have already made their closest approach and are rushing away from each other. NGC 4490 itself is of SBd type, NGC 4485 is an irregular galaxy. NGC4490 is also of cosmological interest as its satellite system - like the one for the Milky Way and Andromeda - seems to align in a plane-like structure, which is not easy to explain in the standard structure formation scenario.

Observation Notes

Owing to its interaction, there is considerable star formation in both galaxies as being evident by the copious Halpha emission. Consequently the object is quite blue. when color calibrating the image with SPCC, I therefore used Sdm as the color references, i.e. calibrated against much bluer object than the average spiral. This helped to emphasize the yellow-brownish dust bands in NGC 4490 a bit more.

Data were taken on 2025 April 12 and 19-22

Technical Details

View the full-resolution image together with complete acquisition and processing details on AstroBin.