Arp’s Peculiar Galaxies
Page 10 of 11
Arp observations 91-100 of 110 total to date.
| Thumbnail | Title/link | Arp Category | Date Observed | Observer Description |
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Arp 278 / NGC 7253A-B | Interacting galaxies | 2023-10-23 00:00:00 | This was my first direct experience with capturing an "Arp Peculiar Galaxy" while participating in the Cloudy Nights EAA Forum October 2023 Challenge. I struggled mightily to find it, since I had not extended SharpCap's library to include the Arps, and the coordinates I found online were J2022, not the J2000 that SharpCap requires. Once I found the target, it was a straight forward capture, which I enjoyed immensely. It certainly shows two galaxies interacting. Most would say "merging" but I didn't appreciate the depths of that controversy at the time. Anyway, I fully enjoyed this observation and it predisposed me to take on the AL challenge when I learned about it a few months later. |
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Arp 279 / NGC 1253 | Interacting galaxies | 2025-01-24 20:54:00 | This is really a remarkable testimony to how sensitive the Apollo M-Mini camera really is. Under 5 minutes and it shows everything necessary. Not the "beautiful" capture I would have liked. But clouds rolled in. The two galaxies are obviously interacting... you can see the little nub on the large galaxy towards the small one as well as the extended spiral arm on the opposite side. The only thing you can't see in this capture is the dust halo around both galaxies, particularly the smaller one. But I'm not sure it adds much to the story in this case. |
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Arp 280 / NGC 3769 | Interacting galaxies | 2024-04-21 23:53:00 | NGC 3769 is an elongated, barred spiral galaxy of magnitude 11.7, while NGC 3769a, located in the right of the image, and slightly obscured, is magnitude 14.7. Below (north) of NGC 3769 is a small smudge described as a 'knot' in the Arp atlas, which could be a dwarf galaxy. they are clearly "interacting". Most astronomers would, today, say "merging". |
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Arp 281 / Whale Galaxy | Galaxies with infall and attraction | 2024-02-19 00:00:55 | This is a large, relatively bright target which is fun to capture. Arp categorizes this as a galaxy "with infall and attraction", where the most obvious sign is the small galaxy NGC 4627. This appears to the right of the whale, just below center. The "Whale" appears to be an unusually thick spiral galaxy viewed edge-on, with no obvious, additional bulge in the center. There is a small bump towards the top left of the galaxy (the whale's "head") which may be evidence of a prior infall. The Oxford online dictionary defines "infall" this way: "the falling of small objects or other matter on to or into a larger body". This is as close as Arp gets to the concept of "merger", though infall implicitly excludes the notion of peer galaxies coming together. Arp notes, "Diffuse counter tail on companion [NGC 4627]". It's not clearly visible on the color images, but shows up (semi-distinctly) on the inverted rendering (and, of course, is very clear in Arp's). |
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Arp 282 / NGC 169-169A | Galaxies with infall and attraction | 2024-12-12 21:42:00 | Considering this was captured on a 93% moonlit night, it's pretty amazing, and testament to the power of the Apollo M-mini mono camera. All of the key details, particularly the dust trail to the lower right on IC 1559 (the dwarf galaxy), are visible, which I interpret as stars left behind while the bulk of the dwarf galaxy is drawn into a merger with NGC 169. It's even more clear in an inverted rendering of my image. As usual I prepared a direct comparison with the plate published in Arp's Atlas of Peculiar Galaxy, which shows the ultimate image using 1960s technology. I couldn't resist adding a Hubble Space Telescope image I found on Wikimedia Commons, licensed under a Creative Commons 2.0 license (and anyway, as based on Hubble data, inherently public domain). This shows how much technology improved in roughly 40 years. Of course the idea that I could capture an inferior, albeit adequate, image in half an hour from my back yard is mind blowing. I would have extended the capture, but high clouds were starting to trigger brightness filtering so I shut this capture and moved to another part of the sky. |
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Arp 284 / NGC 7714 / NGC 7715 | Galaxies with infall and attraction | 2023-10-10 22:30:32 | There are two obvious galaxies in the frame: NGC 7714 is a distorted, more or less round, spiral galaxy in the center of the image that appears to be attracting stellar material from above and below. Below, the new material deformed a large spiral arm, out- and downwards. 7714 has a very bright galactic nucleus and the rest of the spiral disk is bright and well formed. NGC 7715 is much less bright, with a dim center. We appear to be viewing it edge-on, distorted into an integral sign shape that runs right to the edge (and behind?) 7714. The fact that 7714 is brighter and more intact suggests it is the dominant galaxy of the two. I'm wondering if the bright spot just below 7714 is a dwarf companion also in the process of "infall". Arp doesn't mention it in his notes, so may not be likely. Still it does have a suspiciously companion-like structure. |
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Arp 285 / NGC 2854 / NGC 2856 | Galaxies with infall and attraction | 2024-02-05 00:23:30 | Captured in a combined image with Arp 1. These two emerged first, substantially brighter than Arp 1. The foreground galaxy, NGC 2854, is a spiral, barred galaxy forming an extended "S" curve pointing directly to NGC 2866 with a hint of a dust lane connecting them (seen more clearly in the Arp plate); NGC 2856 is a more regular, compact spiral. A jet visible in the Arp plate shoots in the general direction of Arp 1, explaining Arp's description that a "Narrow tail leads away from northern nucleus." The "jet" is not visible in my capture neither in color nor inverted grayscale. |
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Arp 286 / NGC 5560-5566-5569 | Galaxies with infall and attraction | 2024-06-07 23:07:00 | Captured during a brief, clear window during an otherwise cloudy new-moon night. Transparency was suspect though SharpCap's brightness filter stayed quiet until near the end of the capture. Arp 286 embodies 3 wildly interacting galaxies. NGC 5566 is the elongated spiral galaxy in the center; lower-diagonal-left is NGC 5569, a dwarf spiral with extensive filaments connecting it to 5566. These can be readily seen both in my inverted image, and in Arp's. One small arm of 5566 has been pulled away slightly by the interaction. Switching to NGC 5560 (upper-left), it is an extreme barred spiral, with the lower arm pulled towards 5566 and exhibiting filaments "nearly" connecting them. The classic S curve of such galaxies in this case is slightly asymmetrical, and expanded in the direction of 5566. The filaments are also longer in that direction. Arp remarks that "Connection not visible", presumably describing this connection since the other does appear visible. Ultimately, I presume that both of the smaller galaxies will end up merged into 5566, though it's possible 5560 has already "missed" 5566 and is now moving away. The extreme barred structure suggests it's been interacting for a very long time. |
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Arp 298 / NGC 7469 with IC 5283 | Unclassified double galaxies | 2024-10-28 22:26:00 | This is one of the more unusual Arp Catalog entires: two galaxies in close proximity. The only suggestion that they are interacting is a slight twisting of an arm in the small galaxy (IC 5283) towards NGC 7469, an elongated core, and a slight suggestion of a dust trail. NGC 7469 appears to my eyes as being type S0 - aka Lenticular -- intermediate between a spiral and elliptical. There remain clear spiral structure in the core, which is fading in the outer envelope.. |
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Arp 299 / NGC 3690 / IC 694 | Unclassified double galaxies | 2024-05-24 23:07:00 | Another surprisingly good capture given a waning moon just a couple of days past full. Luckily aiming directly away. These galaxies are astonishing. Two appear so well integrated that they have a single NGC number instead of two consecutive, or, as you see often an A/B. They both seemed to be irregular barred galaxies that, by this point, have merged galactic centers. Even Arp seems resigned to the fact in his remarks: "Bright internal knots." The dwarf IC 694 seems to be sucked in from the bottom of the image as well. |