Arp 178 / NGC 5614, 5615, and 5613
| Designation(s) | Arp 178, NGC 5614, NGC 5615, and NGC 5613 |
| Object Type(s) | Galaxy, Galaxy Cluster |
| Relevant Catalog(s) | All (Chron), Arp, NGC |
| Arp Category | Galaxies with narrow counter-tails |
| Obs. Lat/Long | 42° 17', 073° 57' |
| Constellation | Bootes |
| Date and Time Observed | 2025-07-18 22:44:00 |
| Instrument | EdgeHD 8" w/f7 reducer-1,422mm FL |
| Camera | Player One Apollo-M Mini |
| Image Details | Up is 0.7 degrees E of N. Transparency: Excellent. Seeing: Excellent. Total integration time was 31m. Exposures 15s@300g, No Filter. Dithered and recentered in SharpCap. No guiding. |
| Description | This is a truly enigmatic Arp object. At first glance it appears to be two galaxies interacting: NGC 5614 (the large galaxy) and NGC 5613 (the medium sized galaxy above it). Unfortunately, the giant plume (which is the predominant "peculiar" feature" doesn't make any sense in that context. It starts to make sense when you realize that the spot on the rim of 5614, close to the right hand edge at the base of the plume, is a dwarf spiral in its own right, NGC 5615. Then, especially after some enhancement, my image reveals some structure: a brighter tidal tail the width of NGC 5615 within the larger, much more diffuse plume that appears nearly structureless. In the first instance, it seems like this was formed by detritus left behind when 5615 was ripped out of a likely orbit (R to L). Arp's remarks, "Ring off center, broad ejected plume from condensation in ring," frankly seem to miss the point. It's one of the fun things about observing Arps is that while you always need to take Arp seriously, his interpretations are sometimes wrong, and this seems to be a case of this. I would suggest the plume wasn't ejected, it was left behind in the absorption of 5615, and then potentially made more diffuse via interaction with 5613. |
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