Object name: ARP256
Designation(s): ARP256, PGC 001224, PGC 001221,
Arp 256 consists of two interacting galaxies; MCG -02-01-051/PGC 001224 (lower) and MCG -02-01-052/PGC 001221 (upper) at a distance of about 355 million light years. Arp classed them as; Galaxies not classifiable as S or E; Appearance of fission. Using standard galaxy classification the upper one is classed as SBc pec while the lower as SBb pec? So both are considered barred spirals. One note says of the upper galaxy; "It is possible that it alone consists of two overlapping galaxies." Hubble has taken an excellent image of this pair, it is at: http://www.spacetelescope.org/images/heic0810ag/ I'm not sure if it answers the question about it being two galaxies or not. That blue knot between the cores of the two galaxies may be a third galaxy. It carries a redshift that is a bit higher than either of the two galaxy cores. It is about the same as the smaller area of blue stars north of the core of the upper galaxy. Thus there seems to be an overlay of blue stars with a slightly greater redshift (by about 40 to 80 km/s). Whether this is a separate system I don't know. More likely the difference is just due to rotation of the galaxy in a plane tilted a bit away from us. The lower galaxy MCG-02-01-051 has a very interesting tidal tail to the west and in the Hubble image, it too has some of these super hot blue stars that may really be related to the other blue stars rather than the galaxy itself. Note how wild its core is as seen by Hubble.
Related Designation(s):2MASS J00185014-1021417, 2MASS J00185087-1022365, 2MASX J00185015-1021414, 2MASX J00185089-1022364, 6dF J0018500-102142, 6dF J0018501-102142, 6dF J0018509-102237, AKARI J0018508-102239, ARP 256, ARP 256 NED01, ARP 256 NED02, ARP 256N, ARP 256S, ARP256, ASK 126344.0, ASK 126345.0, FBQS J0018-1022, FIRST J001850.8-102236, GALEXASC J001850.93-102236.9 , GALEXMSC J001850.90-102236.9 , GSC 5264 00962, HOLM 007, HOLM 007A, HOLM 007B, IRAS 00163-1039, IRAS F00163-1039, MBG 00163-1039, MCG -02-01-051, MCG -02-01-052, NSA 021869, NVSS J001849-102129, NVSS J001850-102234, PB 08114, PB 08115, PGC 001221, PGC 001224, SDSS J001850.13-102141.6, SDSS J001850.87-102236.6, SDSS J001850.87-102236.7, SDSS J001850.88-102236.6, SDSS J001850.88-102236.7, SSTSL2 J001850.87-102237.4, VIII Zw 018, VIII Zw 018 NED01, VIII Zw 018 NED02, VV 352, VV 352a, VV 352b, [RHM2006] LIRGs 043, [S87a] 03A, [S87a] 03B, [SLW2012] 002, [ZSK75] 0016.3-1037, [ZSK75] 0016.3-1037 NED01, [ZSK75] 0016.3-1037 NED02,