Object name: ARP106

Designation(s): ARP106,

Arp 106 is an interacting pair of galaxies in Coma Berenices about 315 million light-years away. Arp put it in his category of elliptical and elliptical-like galaxies connected to spirals. He made no comment on this entry.

The two galaxies are known as NGC 4211. While some catalogs give only one number to both a few do have separate numbers. MGC +5-29-042 is the northern member and MGC +5-29-043 is the southern to give one example. NED classes both as S0/a pec. I would say the southern one is likely S0 but the upper appears to be a distorted Sa or possibly Sb spiral to me. In any case, both have been severely disrupted by their interaction. They have somewhat different redshifts. I don't know if that will be enough to prevent them from merging in the future or not. I rather suspect they will merge eventually becoming an elliptical galaxy. Note that there appears to be a faint plume east of the southern well-defined plume. I see hints of it in the Sloan image as well. NGC 4211 was discovered by Édouard Stephan on April 30, 1881. I don't know if he saw the companion or not. I suspect he didn't.

Just west of the pair is LEDA 1828543 (SDSS J121521.05+281048.0), a spiral galaxy that is likely a member of the same group as Arp 106 as its redshift is practically the same.

Toward the southwest (lower right) corner is an object that NED shows as being a quasar in some catalogs, an IR source only in the 2MASX catalog, a star in the Sloan survey and a galaxy at a slightly different position (0.1" different in declination). NED shows two redshifts, one is z=0.692000, the other is z = 4.88922! Now that's a discrepancy. The distance I used on the annotated image is based on the lower z value which puts it 6.3 billion light-years away. The other value would put it over 12.4 billion light years which would mean it is brighter than any quasar I ever heard of. The lower value is even surprising considering its magnitude of 17.8.

An interesting galaxy at 670 million light years is SDSS J121522.43+280406.9 south-southwest of Arp 106. It seems to have one heavy arm on the south. It would fit in either Arp's one arm category or heavy arm category.

Arp's image

14" LX200R @ f/10, L=4x10' RBG=2x10'x3, STL-11000XM, Paramount ME