Arp’s Peculiar Galaxies
Page 6 of 7
Arp observations 51-60 of 70 total to date.
| Thumbnail | Title/link | Arp Category | Date Observed | Observer Description |
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Arp 225 / NGC 2655 | Galaxies with amorphous spiral arms | 2024-02-29 00:00:45 | Amorphous spiral arms indeed! During capture they were just perceptible on my SharpCap live stack, which means that post-processing was required to make them visible in the final web images. The core and central disk are quite evident, but the arms are diaphanous. If they contained more stars this would look like the Pinwheel Galaxy! |
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Arp 233 | Galaxies with the appearance of fission | 2024-02-21 00:00:35 | This is a tiny object which stresses the limits of my 8" SCT with 294 sensor. The featured image reproduced here is only 158 pixels in the original capture where it appears as an elongated blob. Given that Arp described this as a galaxy "with the appearance of fission", I processed the SharpCap .png in Affinity Photo to emphasize the asymmetry within the capture. After processing, a slight elongation at approximately 190 degrees relative-rotation is more evident. Nevertheless, of the 23 Arp Galaxies so categorized (Arp 233-256), this is the most "normal" looking and least obvious fissioning galaxy in the series, even with the benefit of the 200" Hale Telescope's resolution. |
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Arp 244 / Antennae Galaxies | Galaxies with the appearance of fission | 2024-05-02 22:17:00 | First observation of the night, on an evening when it wasn't forecast to be clear at all. Turned out to be clear enough, though we struggled with some high clouds. We'd decided to capture 30 minutes, but cut things short by 30s when the brightness filter on SharpCap rejected the last 5 lights. The dust lanes which appear to show ejecta from each of the two galaxies are quite evident; if you can't see them, please boost the brightness on your monitor. This does appear to show two galaxies in a well-advanced merger: the original spiral structures are heavily distorted; somewhat evident in NGC 4038 (right), and largely destroyed in 4039. While the notion of a merger is well accepted now, Arp usually interpreted galaxies as breaking apart or ejecting matter. Hence his categorization of these "with the appearance of fission". |
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Arp 268 / Holmberg II / UGC 4305 | Galaxies with irregular clumps | 2024-03-26 00:01:45 | This appears to be an irregular dwarf galaxy with low surface brightness, and a series of small structures above the surface. They remind me of structures I've seen in other contexts, similar to NGC 604 outside of the Triangulum Galaxy, or even M42 within our own galaxy. Certainly they could be star birthing regions. Considering this was a full moon, I was pleased with this capture in SharpCap. |
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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, the other small and spiral. |
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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 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 object due to so-so transparency, but decided it had cleared up enough at 1:30 AM. Wonderful, relatively bright observation showing two spriral galaxies heavily interacting. Whether it's a future merger or a near miss is beyond my expertise, but the exchange is clearly visible. |
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Arp 278 / NGC 7253A-B | Interacting galaxies | 2023-10-23 00:00:00 | This was my first direct experience with "Arp Peculiar Galaxies" while participating in the Cloudy Nights EAA Forum October Challenge. Once I found the target, it was a straight forward capture, which I enjoyed immensely. It appears to be two galaxies merging. Is it possible that the galaxy on the right previously absorbed another galaxy? That could explain the downward bend of its disk. |
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Arp 280 / NGC 3769 | Interacting galaxies | 2024-04-21 23:53:00 | NGC 3769 is an elongated, 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. |
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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. |