We have a big disadvantage as astrophotographers trying to understand the nature of galaxies, as well as a big advantage. The disadvantage is that we only see galaxies as snapshots in time, with no hope of seeing significant changes during our lifetimes. The advantage is that we can examine galaxies throughout the sky that are in different stages of formation, and use that knowledge to shape our understanding of them. Similar to how aliens, looking down from above earth at a single point in time, could obtain a decent understanding of human development just by observing humans in different stages of life, from infant to elderly.
This poster captures images of galaxies that, it appears to me through visual examination, are in the final stages of a merger. By this point in time, both the disks and the cores of both galaxies have combined to some extent. It is hard to imagine the scale and forces involved in these interactions.
My favorite aspect of these objects are the twisted, chaotic dust lanes that often result. Because of these dust lanes, I believe that at least one of the galaxies of each of these objects was a spiral galaxy in its former life.
As stated on the poster, here are some of the common characteristics of these late stage merger objects:
- - Asymmetric overall shape
- - No clear sign of previous galaxy structures
- - Bright single central glowing core, often spherical
- - No spiral outer disk
- - Strong central dust band across core
- - Chaotic dust band path
- - Arcing, sometimes looping, extended star streams
It is interesting to me that Dr. Arp didn’t have a Merger category for these wonderful objects. His view was that galaxies were splitting apart, not merging. A few of the objects on this poster were included in the Arp category entitled, “Galaxies - Disturbed with Interior Absorption”.
If you would like to read more about any of these objects, they each have been uploaded and described individually on my Astrobin site. They all reside in my Astrobin
Late Stage Mergers Collection.
If you would like to access all my DSO compilation posters, please click
here.
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