Arp’s Peculiar Galaxies
Page 6 of 9
Arp observations 51-60 of 88 total to date.
| Thumbnail | Title/link | Arp Category | Date Observed | Observer Description |
|---|---|---|---|---|
 |
Arp 169 / NGC 7236-7237 | Galaxies with diffuse counter-tails | 2024-10-27 21:24:00 | This appears to be a string of 3 galaxy centers -- NGC 7236, 7237, and the tiny one: NGC 7237C -- that share a common envelope of stars. 7236's envelope is extended to the left, while 7237 and 7237c's extemd slightly to the right. My guess it's caused by the galaxies approaching from different directions, and with different initial motions... the far ends of each galaxy's star envelope slowed more slowly than the envelope closer to the others, causing them to stretch out. |
 |
Arp 170 / NGC 7578 | Galaxies with diffuse counter-tails | 2024-11-03 22:17:00 | At the heart of Arp 170 is a merged, curved, diffuse envelope of what (from the shape) are at least two elliptical galaxies. However, a total of 5 or 6 possible galactic nucleii track the same curve as the envelope. Are they all galactic cores, or are some asterisms? I can't tell and even the Palomar image doesn't disambiguate it much. |
 |
Arp 176 / NGC 4933 | Galaxies with narrow counter-tails | 2024-04-16 23:55:00 | This is a tiny cluster of 3 galaxies: NGC 4933 A/B/C. B is the tail galaxy which appears to be a small elliptical galaxy viewed edge-on. A is the middle galaxy, and c is the dim little nub just west of the other 2. The two brighter galaxies are Magnitude 13, and clearly interacting. C is magnitude 18.5 and does not seem to be interacting with the others. Given it's small size, it's likely to be much futher away. |
 |
Arp 182 / NGC 7674 and 7675 / Hickson 96 | Galaxies with narrow filaments | 2024-11-03 23:08:00 | Arp 182 displays two faint filaments extending from what otherwise appears to be an intact spiral galaxy: The first is an extremely subtle extension more or less down, slightly skewed in the direction of NGC 7675. I'm frankly not sure it's visible in my image (and perhaps I think I see it due to confirmation bias) and is barely visible in Arp's published image. Slightly more obvious is semi-circular filament extending up and to the left, which I can reliably perceive in my 45m capture. It leaves me wondering about the relative motion of two small galaxies: one almost directly to the left the other straight up. Interestingly, Arp didn't include these in the atlas photo of Arp 182. Perhaps they are outside the FOV of his telescope? They do seem relevant to understanding the filament's shape and direction. |
 |
Arp 184 / NGC 1961 | Galaxies with narrow filaments | 2024-02-29 00:00:59 | This was an enjoyable capture, and after 40m of integration I shut things down thinking I'd done a great job. However, I hadn't focused on the peculiarity of this galaxy, which was, "Galaxies with narrow filaments". Turns out I had been fooled by the bright galactic center and disk, not recognizing that the filaments were MUCH less bright. My initial attempt with the color image was pretty poor. After using a mono camera starting in late October of 2024, I gained experience in post-processing mono images to bring out faint filaments. So on Election Day (November 5) I decided to convert this image to mono and try the same techniques. They turned out pretty well: the filaments are clearly visible. |
 |
Arp 185 / NGC 6217 | Galaxies with narrow filaments | 2024-05-23 23:56:00 | This is a relatively large and bright barred spiral Arp galaxy, located high in the sky in Ursa Minor, and observable in almost precisely the opposite direction from the nearly full moon. Unfortunately, there was a relatively faint satellite trail that passed close to the image towards the end of the capture. The dust lanes that extend the arms of the galaxy are visible but less than might have emerged on a darker night. I was reluctant to extend the capture because the moon was continuing to rise, and it seemed to me that more time might wash out the dust lanes. The filaments are reasonably symmetrical, and fill out a classic "spiral" galaxy shape albeit with much less stellar mass than in a more mature galaxy. I guessed that this is a relatively young galaxy still actively making stars, later confirmed by the Wikipedia write-up. |
 |
Arp 188 / Tadpole Galaxy / UGC 10214 | Galaxies with narrow filaments | 2024-10-24 20:19:00 | Something dragged out the tail, but it's not immediately apparent what. |
 |
Arp 189 / Umbrella Galaxy / NGC 4651 | Galaxies with narrow filaments | 2024-05-01 22:38:00 | This is a very bright and reasonably large galaxy, where the "handle", a faint, vertical dust lane, became evident after about 30m of integration. Clouds shut down observing after 55m. Affinity Photo processing of the .png image saved "as adjusted" in Sharpcap makes it more apparent at the cost of a much noisier background. In most other respects this spiral galaxy appears normal. It is slightly elongated vertically, and the outer arm of the spiral is slightly detached from the rest of the disc, both consistent with a gravitational attraction from the top of the image. |
 |
Arp 205 / NGC 3448 | Galaxies with material ejected from nuclei | 2024-04-22 23:10:00 | NGC 3448 was discovered by William Herschel in 1789. Impressive when you appreciate he was observing by eye. He did not discover UGC 6016 which is the smudge you can see in the upper part of the image, just right of center, a 17th magnitude dwarf galaxy. NGC 3448 seems to have two nuclei, which is presumably why Arp describes it as depicting "material ejected". That may be, though it seems more likely that this is the result of an incomplete galaxy merger. I find it impressive that despite the full moon, with some processing, I was able to capture not only NGC 6016 but also hints of the dust lanes connecting it to NGC 3448. |
 |
Arp 206 / NGC 3432 | Galaxies with material ejected from nuclei | 2024-04-21 23:15:00 | Arp 206 consists of an edge-on spiral galaxy (NGC 3432) of magnitude 11.3 interacting with a magnitude 16.3 galaxy, UGC 5983 (the little smudge to the right and slightly higher). There does seem to be a suggestion of a second interacting galaxy in the opposite direction, in the same plane as NGC 3432. Both may be represent what Arp categorizes as "material ejected from nuclei", though it seems equally likely that the materials may be in a merger process. |