AM 0213-283 was included to sample of Arp (1981). He reported his measurements of the redshifts in this system and noted:
The central object is a very disturbed spiral. High resolution photographs in the following paper indicate that the companion SE is on the end of a spiral arm, and the companion N is strongly interacting. The spectrum of the companion N shows strong, high excitation emission lines.
Companion N is the object 2 in Figure 2 and Table below. It has discordant redshift compared to the main galaxy (object 1). “Following paper” in quote above is Arp (1982). In that paper, Arp said of this system:
Note particularly the strong tail or jet curving out of companion B to the west. Most important of all, note the short spiral arm segments curving from the center of the disturbed spiral directly to companion B. Regardless of what the redshifts of the other galaxies in the vicinity may turn out to be, the evidence of interaction of companion B with the central galaxy is so strong, in my opinion, that the Δz = +14,021 km s-1 redshift discrepancy must be accepted as real and therefore as principally nonvelocity.
Figure 1 below shows an extract of the high resolution photograph presented in Arp (1982) of this system. I have added the marking of the discordant redshift “companion B”.
Sharp (1985) studied the interaction in the system and found no evidence of interaction between the main galaxy and the discordant redshift companion. Sharp did find evidence of interaction between the main galaxy and the non-discordant redshift companion. Sharp also measured redshifts of some nearby galaxies and found some of them to have similar redshift than the discordant redshift companion. Sharp’s conclusions:
The lack of any dynamical disturbance in the main galaxy near the anomalous companion B, contrasted with the disturbed arm stretching to the nonanomalous companion A, is clear evidence against any interaction between B and the main galaxy. For this reason alone, it is not necessary to postulate that the galaxy called B has a noncosmological redshift. In addition, at least two, and possibly three, nearby galaxies of small angular size have redshifts comparable to that of B, with similar emission-line structure in at least one, and probably two, of them. It seems that this system is a coincidental projection of a foreground interacting pair on a distant background group.
Figure 2 shows the objects with measured redshifts in the AM 0213-283 field. Object 7 also has similar redshift to AM 0213-283, so there seems to be a galaxy group at that redshift and not just an interacting pair.
Object 4 doesn’t belong to either galaxy group – it has redshift of about z = 0.3.
Objects and their data
|1||AM 0213-283||Sc||0.035161 (10541 km/s)||15.11||0|
|2||[A81] 021344-2833N||galaxy||0.082040 (24595 km/s)||-||0.231|
|3||[A81] 021344-2833SE||galaxy||0.035948 (10777 km/s)||17.0 (r)||0.447|
|5||2dFGRS S308Z130||galaxy||0.082200 (24643 km/s)||19.05||0.997|
|6||2dFGRS S307Z023||galaxy||0.082000 (24583 km/s)||19.20||1.087|
|7||LEDA 3210176||galaxy||0.035736 (10713 km/s)||17.96||1.211|
|8||2dFGRS S308Z127||galaxy||0.082914 (24857 km/s)||19.38||1.904|
Arp, H., 1981, Astrophysical Journal Supplement Series, vol. 46, May 1981, p. 75-112, “Spectroscopic measures of galaxies, their companions, and peculiar galaxies in the southern hemisphere”
Arp, H., 1982, Astrophysical Journal, Part 1, vol. 256, May 1, 1982, p. 54-74, “Characteristics of companion galaxies”
Sharp, N. A., 1985, Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 297, Oct. 1, 1985, p. 90-97, “Anomalous redshift companion galaxies – 0213-2836″