NGC 0010 – some pair alignments

To my knowledge, NGC 0010 has not been discussed as a discordant redshift system before. Of nearby objects, there is one, object 3 in Figure 1, that has similar redshift as NGC 0010. Object 3 is therefore a probable companion to NGC 0010, and it has about 20 km/s higher radial velocity than NGC 0010, according to nominal values in NED. Only other object that can be considered as a companion is object 2, but it has about 1900 km/s lower radial velocity than NGC 0010, which is generally considered too high velocity difference, so it is not likely to be physically associated to NGC 0010 in traditional view. Small apparent size of object 2 suggests that it is some kind of dwarf galaxy. Only object within 20 arcmin from object 2 with similar redshift is 2dFGRS S495Z200 with cz = 4317 km/s and about 15 arcmin angular distance from object 2. 2dFGRS S495Z200 also seems to be quite a small galaxy.

Object 5 is a star, but there’s a galaxy-like object right next to it. One wonders if 2dF galaxy redshift survey’s target selection made a little mistake there and measured the star instead of the galaxy in almost the same position (the galaxy’s redshift would have been interesting to find out, as it seems to be almost exactly aligned across NGC 0010 with object 3).

There’s a rough pair alignment across NGC 0010 with objects 4 and 8. Redshifts of the two are not particularly close to each other but not radically different, either. Alignment is roughly along the minor axis of NGC 0010. The two objects are quite similar in appearance and their magnitudes are quite similar.

Objects 6 and 9 are roughly aligned across NGC 0010. Redshifts of the two are quite close to each other. The two objects are quite similar in appearance and their magnitudes are not that far from each other. Alignment is roughly along the major axis of NGC 0010, and quite accurately perpendicular to alignment line of objects 4 and 8. Other option for pair alignment is objects 7 and 9, but that alignment is worse than in the pair of 6 and 9, and redshifts are not so close to each other as in 6 – 9 pair, but still quite close.

Objects 8 and 9 have the same redshift, so they are a probable galaxy pair or members of same galaxy group. Looking further out from NGC 0010, there are few objects with almost the same redshift so there might be a loose galaxy group present at that redshift.

Figure 1. Objects with available redshift near NGC 0010 (all objects except one within 10 arcmin are presented). Size of the image is 15 x 15 arcmin. Image is from Digitized Sky Survey (POSS2/UKSTU Blue) and it has been adjusted for brightness and contrast to bring out fainter objects more clearly.

Objects and their data

1 NGC 0010 SAB(rs)bc HII 0.022719 (6811 km/s) 13.3 0
2 2dFGRS S495Z164 galaxy 0.016400 (4917 km/s) 18.84 3.761
3 2dFGRS S495Z331 galaxy 0.022800 (6835 km/s) 18.02 5.068
4 2dFGRS S495Z152 galaxy 0.072000 (21585 km/s) 18.71 5.528
5 2dFGRS S495Z158 star 0.000200 (60 km/s) 19.30 6.738
6 2dFGRS S495Z146 galaxy 0.092600 (27761 km/s) 18.62 6.947
7 2dFGRS S495Z150 galaxy 0.149400 19.13 8.144
8 2dFGRS S495Z182 galaxy 0.114500 19.24 8.252
9 2dFGRS S495Z335 galaxy 0.114400 19.28 9.062

NED objects within 10′ from NGC 0010.

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