AM 0058-402 – bridged discordant redshift objects

Arp (1980) reported three new discordant redshift cases. One of the reported systems was AM 0058-402. This system has main galaxy (object 1) connected to an apparent companion (object 2) galaxy with a spiral arm-like bridge. Problem is that main galaxy has radial velocity cz = 6773 km/s while the companion has radial velocity 16415 km/s, so the difference in these velocities is too large for them to be physically connected in traditional view. Arp says this about the bridge:

On this latter higher-resolution photograph, it is seen that the connecting filament is in the nature of a spiral arm emerging from the larger galaxy. But the arm is much longer than any of the other arms in the galaxy, emerges orthogonally rather than tangentially from the main body, and terminates directly at the center of the companion.

Notes

Figure 1 shows nearest objects with measured redshifts in AM 0058-402 field.

– The bridged object, object 2, seems to belong to a group of galaxies at about 16500 km/s. Object 19 (which is just outside the pictured field) is brightest and seemingly largest of the galaxies in this group, and might be the main galaxy of the group. Objects in the group (within this field) are 2, 6, 7, 8, 11, 16, and 19.

– There seems to be another group at redshift z = 0.177. This group seems to be overlapping with the 16500 km/s group described above. Objects in this group are 9, 10, 13, 14, and 17.

– Objects 12 and 15 are roughly aligned across object 1. Object 3 also falls to their alignment line.

AM0058_402
Figure 2. The objects with measured redshifts near AM 0058-402. Size of the image is about 15 x 15 arcmin. Image is from Digitized Sky Survey. Click for larger version of the image.

Objects and their data

NBR NAME TYPE REDSHIFT MAG SEPARATION
1 MCG -07-03-005 spiral 0.022592 (6773 km/s) 14.5 0
2 PGC 003633 galaxy 0.054755 (16415 km/s) 15.6 (I) 0.426
3 ESP 40160 galaxy 0.105483 18.60 0.948
4 ESP 38602 galaxy 0.223564 19.21 2.551
5 ESP 38632 galaxy 0.115486 19.13 3.021
6 ESP 38526 galaxy 0.055215 (16553 km/s) 19.18 3.706
7 ESP 40626 galaxy 0.053981 (16183 km/s) 17.33 4.657
8 ESP 40625 galaxy 0.054845 (16442 km/s) 17.86 6.093
9 ESP 40187 galaxy 0.179334 18.29 6.479
10 ESP 40161 galaxy 0.177549 18.65 6.733
11 ESP 38528 galaxy 0.055582 (16663 km/s) 18.84 6.858
12 ESP 38482 galaxy 0.188030 19.38 6.875
13 ESP 38605 galaxy 0.176455 18.94 6.912
14 ESP 38669 galaxy 0.177936 18.99 7.119
15 ESP 38704 galaxy 0.107267 19.03 7.224
16 ESP 38529 galaxy 0.054858 (16446 km/s) 18.84 7.258
17 ESP 40188 galaxy 0.179994 18.72 7.799
18 [VCV2001] J010031.5-401351 QSO 0.610000 17.90 7.958
19 LEDA 101141 E 0.054948 (16473 km/s) 16.17 7.961
20 ESP 38483 galaxy 0.159123 18.95 8.449

NED objects within 10′ from AM 0058-402

References

Arp, H. 1980, Astrophysical Journal, Part 1, vol. 239, July 15, 1980, p. 469-471, 473, 474, “Three new cases of galaxies with large discrepant redshifts”

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4 Responses

  1. You mean apparent velocity, not radial velocity, right? PGC 003633 isn’t spinning around MCG -07-03-005 that fast 🙂

    Is there any other information about PGC 003633?

  2. As you can see here, using “radial velocity” for cz is common “therminology”. I’ll see if I can find anything new on the companion.

    • Of all things, I did not know that was just another term for the implied velocity of the spectrum. Of course, I don’t like the term because it implies something physical that may not be there, but now I’ll understand it when you say it again 🙂

      I was just wondering whether there was any information on whether the companion is one of the expected young objects (late-type spiral? something without arms of its own yet?) post-ejection or not.

  3. There’s not much information available on the companion. I think it’s all in the NED page of the object. No knowledge of what kind of object it is. With luck there might be a newer and better image of the system somewhere, but I doubt it (see Arp 1980, linked above, for best available image I’m aware of).

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