Arp’s Peculiar Galaxies
Page 13 of 16
Arp observations 121-130 of 155 total to date.
| Thumbnail | Title/link | Arp Category | Date Observed | Observer Description |
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Arp 269 / Cocoon Galaxy | Galaxies with connected arms | 2024-02-19 17:55:00 | This is just a fun EAA object. Relatively large with lots of detail. Loved capturing it! The connected arms appear to have been separate galaxies at one point... one large and distorted (NGC 4490), the other small and spiral (NGC 4485). In the gallery you'll find a second observation made using the same EdgeHD telescope, but with the 0.7x reducer and the Apollo M-mini mono camera. 44m of integration time. It does a better job of revealing the halos surrounding both galaxies, especially in the inverted view. I'm guessing that this is caused by new star formation stimulated by the interaction. This is not based on research, but observing similar phenomena in other Arp galaxies that astronomers interpreted that way. |
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Arp 270 / NGC 3395-6 | Galaxies with connected arms | 2024-05-31 22:54:00 | Two strongly interacting galaxies, both spiral originally and now significantly distorted by the interaction. There is a tiny and very faint galaxy, IC 2605 which appears to extend the right arm of NGC 3395, the upper galaxy in our image. It's not at all obvious, but showed up in the Astrometry annotation. It has a higher redshift than the two larger galaxies, and is apparently far in the background. Arp famously argued that galaxies with different red shifts could interact, but this apparently is not one of those examples. |
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Arp 271 / NGC 5426 / NGC 5427 | Galaxies with connected arms | 2024-05-13 01:55:00 | Captured at the end of a long evening. I'd been focused on Messier objects due to so-so transparency, but decided it had cleared up enough at 1:30 AM. Wonderful, relatively bright observation showing two spiral galaxies heavily interacting. Whether it's a future merger or a near miss is beyond my expertise, but the exchange is clearly visible. Arp remarked: "Arms linked. Note bifurcation in arm of N spiral." I believe Arp is describing the bottom arm of NGC 5427 which is rooted in another arm rather than in the nucleus. There is actually faint glow at the point of intersection. I'm tempted to speculate but won't. |
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Arp 272 / NGC 6050 / IC 1179 | Galaxies with connected arms | 2025-06-30 01:09:00 | Arp placed this in the "Double Galaxies - Connected Arms" category. His observing notes added: "Arms join at dense knot or nucleus...." My interpretation from the beginning was that we were really looking at 3 galaxies: NGC 6050 (lower left), IC 1179 (upper right) and a third, smaller galaxy at the end of NGC 6050's arm (upper left). Arp's comment suggests he saw the nucleus but wasn't willing to suggest it's a 3rd galaxy. My research discovered the Hubble image you can find in the gallery which confirms it is a third galaxy. |
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Arp 273 / UGC 1810 / UGC 1813 | Galaxies with connected arms | 2024-11-05 20:51:00 | This is a very mysterious duo of galaxies. The smaller, to the left, appears like a ribbon because it has been largely stripped of its envelope of stars. The larger, right, is a weirdly distorted, barred spiral, in 3/4 view. To be clear, the bright object in the center is actually a star, not the galactic nucleus. The actual nucleus is just above it, and therefore asymmetrically located within the spiral. The top arm has been pulled left. The bottom half of the spiral is partially stripped and what remains is heavily knotted: this is less obvious in my capture, but very clear in Arp's. I see that some sources explain the mystery by the smaller galaxy having actually passed through the larger. This is certainly consistent with what i can see, particularly in Arp's capture, which I "printed" as a positive image because I felt it showed the chaos better. |
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Arp 276 / NGC 935 and IC 1801 | Spiral galaxies with elliptical companions on arms | 2025-11-22 19:34:00 | This target was captured on a dark night, with only so-so seeing. This is a classic Arp object, relatively large and bright by comparison to many. Arp's comment is simply: "Both intersecting edges seem dimmed. " which is true enough but leaves me wondering why it matters. This seems another example where Arp's fetish against galaxy merger seems misplaced. Because the smaller galaxy attaches at the top of the spiral and not at the end of the big arms, Arp can't call it a "companion". |
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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 / C32 | 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). |