Arp’s Peculiar Galaxies
Page 8 of 18
Arp observations 71-80 of 179 total to date.
| Thumbnail | Title/link | Arp Category | Date Observed | Observer Description |
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Arp 135 / NGC 1023 | Galaxies with nearby fragments | 2024-03-13 11:09:27 | First observation of the evening starting with Astronomical Dusk. Altitude just under 40° at start and setting. This is a relatively large and bright object that appeared almost immediately in SharpCap. Note Arp comparison, inverted, and Hubble image are rotated 180° to match Arp's original image. I frankly struggled to figure out what was the "fragment". Initially I thought it was the tapering dust at the bottom (west) of the close-up images. But in reviewing the capture prior to submission I re-thought that conclusion and started researching. The first clue was found in Hubble's remarks which I have recently learned to access on the CalTech website: "Similar nebulosity about one diameter further east." This drew my attention to the top of the image, and I noticed a slight separation and cant to the left of a gray-blue elliptical shape in my original capture that I had not noticed at the time. This became somewhat more evident when I re-processed my original SharpCap capture, converting it to grayscale and mono-stretched it. Thiese are the second and third images in the gallery (positive and inverted, respectively). Again, this is something I learned to do during this process. Finally, I ran into the Hubble image, which colors "1023A" in blue, which I've attached 4th in the gallery. An interesting example of how going through this process has sharpened my observing skills. |
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Arp 136 with NGC 5821 | Galaxies with nearby fragments | 2025-07-30 23:50:00 | Capture was cut short by clouds... I managed only 13m 15s and had hoped for at least 30m. Amazingly, I think this was "just enough" especially with enhancement. Arp categorizes 136 as an "E[lliptical] or E-like Galaxy with Nearby Fragments". His remarks: "Faint streamers off one end of E galaxy". These are presumably the plume at the right end of the main galaxy, and I presume also that the "fragments" are the little points of light at the end of the plume. |
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Arp 137 / NGC 2914 | Material emanating from elliptical galaxies | 2025-01-26 22:19:00 | This is a bonus object, imaged within the same field of view as Arp 232. I was not aware of their proximity when I captured the observation. I did process this differently with two levels of sharpening to emphasize the separation of the upper arm from the galaxy center. When I created the comparison image, I noticed that the smaller of the double stars to the left (west) of the target has orbited to new position since Arp's image. This is a first for me. As for Arp's classifying this as "material emanating from an elliptical galaxy," I'm not sure he's right. My first clue was the size of the stars. Normally the Arp images are pinpoint compared to my 8" EdgeHD, but here (as you can see in the comparison image) the stars are similarly sized. This suggests to me that Arp's image is overexposed and blew out any detail in the galaxy disk, making it appear elliptical. I then went searching for sources after the fact and discovered Gary Imm's images of Arp 137 that he classifies as a barred spiral. It seems to me that interpreting this image as a spiral galaxy with one extended arm, is more likely, even given Arp's image. Arp may have been excited to find an elliptical emanating material, but may be victim to his own confirmation bias. |
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Arp 138 | NGC 4015 | Material emanating from elliptical galaxies | 2026-04-27 22:15:00 | Arp categorized this as "material emanating from E. galaxies." Most modern observers see instead an edge-on spiral merging with an elliptical. Arp's remarks are hard to interpret, "Absorption leads directly into E galaxy." Absorption has both a technical meaning related to spectroscopy (e.g. absorption lines) and a common-sense meaning. Unclear which Arp intended. However, his bias towards interpreting things ejected from galaxies versus things merging is well known and long standing. |
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Arp 141 / UGC 3730 | Material emanating from elliptical galaxies | 2024-03-24 23:22:32 | A clear night, but a full moon. I searched for Arp targets that would be as far from the moon as possible, and this was the first I came up with... The two nucleii came up almost immediately. The bulbous end next. Eventually the loop structure began to fill in. In reviewing this prior to submission to the AL, I found Arp's category unconvincing. There are no remarks to assist. While it's possible we're seeing "material emanating" it strikes me that material could equally-likely be merging. There is a highly distorted structure to the emanations, and it looks suspiciously like a low surface brightness barred-spiral galaxy getting compressed by (presumably) a much denser elliptical galaxy. Either way it's a "peculiar" galaxy in Arp's terms, but common sense suggests structured material is more likely to be coming in that out. |
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Arp 142 / The Penguin and Egg / NGC 2936 & 2937 | Material emanating from elliptical galaxies | 2026-05-18 22:30:00 | This is one of the classic "peculiar galaxies" due to its evocative appearance. Arp provides no remarks; category is an elliptical galaxy emanating material. Really? An exchange seems equally likely. The small items to the right of the elliptical might be Arp thought were the materials emanating, but it's clear in the JWST image that those are tiny background galaxies. There does seem to be a connection from the north end of the elliptical to the "beak" of the Penguin, but that seems symmetrical. |
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Arp 143 | NGC 2445 & 2444 | Material emanating from elliptical galaxies | 2026-01-22 21:19:00 | This is a classic peculiar galaxy where the interaction between NGC 2445 and 2444, after modern observations, is thought to have stimulated intense star formation along the bridge between them. Most of the bright spots on 2445 (dark in the inverted images) are thought to be new star formation structures as well. From the category, Arp seemed to thing that NGC 2445 "emanated" from the Elliptical galaxy NGC 2444. His remarks, "Diffuse counter filament" is a bit challenging to interpret, though I take it to mean the gray "haze" that shows up in his image, and the "dust" that seems to surround both galaxies in my wider field image. |
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Arp 145 / UGC 1840 | Material emanating from elliptical galaxies | 2024-02-29 20:00:01 | Reviewing this before submission to the AL in Feb 2025, a year after the original capture,, I feel the same about this target as I do Arp 141: this is as likely to be a merger as a showing "emanating material". As part of this "rethinking", I created the inverted monochrome image from my original OSC capture, which depicts things much more clearly in combination with the positive. The galactic center of the elliptical galaxy is obviously the large, medium-bright object just left of image center (the three stars in a line are lower in the image and point to it). All of the other bright objects are imo field stars, EXCEPT the medium bright object which forms the upper vertex of a triangle in combination with the two brightest field stars. If you look at my inverted image, it's the smallest of the three. If believe this could be the center of a spiral galaxy being absorbed into the Elliptical rather than emanating from it. This capture took place despite an 88% moon. I was determined to capture a number of Arp galaxies in Andromeda, recognizing the window of opportunity in Feb 2024 was short. This was the second observation of the evening, and the target was fairly low in the west. I captured as much data as I could until I judged the thicker atmosphere and glow at the horizon would render further integration useless. |
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Arp 150 / NGC 7609 | Galaxies with jets | 2024-11-03 21:36:00 | Arp's designated this cluster as one of a group of "Galaxies with jets." The image suggests that NGC 7609 is in fact two galaxies, a larger one (left) connected to a smaller one by two major arms. The "jet" is likely the emanations from the smaller 7609 galactic center, but that's just a guess. It's more readily seen as an inverted (negative) image, so I prepped the "comparison" accordingly. |
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Arp 151 / Markarian 40 | Galaxies with jets | 2025-05-11 22:42:00 | The first observation following a clear day, but with a full moon. As it turned out clear enough. |