The group contains two Messier objects: M81 and M82 which form an appealing interacting pair visible in the same field of view at moderate magnification. Other members include NGC 3077 and NGC 2976. As radio images such as ours have revealed, NGC 3077 is in considerable interaction with M81 and M82, plus perhaps some very small galaxies, as there is a common gaseous envelope. In our image, M81 is the spiral right and below center, M82 the not in the upper right center, and NGC 3077 is lower left; at least two dwarf galaxies appear to show up closely left of M81.
Further, more outlying members of the group include the irregular galaxy NGC 2366 and the fine Sc spiral NGC 2403, both lying in the constellation Camelopardalis, IC 2574, "Coddington's Nebula", which is quite irregular but shows some "faint indications of spiral structure" (Burnham), and the irregulars Holmberg I (UGC 5139) and Holmberg II (UGC 4305).
A full list of the group, as given by R. Brent Tully in his
Nearby Galaxies Catalog, is given in the table below (added to this is
Holmberg IX):
Name | Name II | RA(h:m) | Dec(d:m) | type | m_v | dim | RV |
---|---|---|---|---|---|---|---|
NGC 2366 | H III.748 | 7:28.9 | +69:13 | Ir+ | 10.91 | 7.3x3.5 | 252 |
NGC 2403 | H V.44 | 7:36.9 | +65:36 | Sc | 8.39 | 17.8x11.0 | 259 |
M81 dw A | 8:23.9 | +71:02 | I? | 16.5: | 1.3x0.7 | 262 | |
Holm. II | UGC 4305 | 8:18.9 | +70:43 | Ir+ | 10.75 | 7.6x6.2 | 305 |
UGC 4459 | 8:34.1 | +66:10 | Ir+ | 14.38p | 1.7x1.3 | 144 | |
Holm. I | UGC 5139 | 9:40.5 | +71:11 | Ir+ | 12.94 | 3.5x3.0 | 287 |
NGC 2976 | H I.285 | 9:47.3 | +67:55 | Scp | 10.15 | 4.9x2.5 | 175 |
M81 | NGC 3031 | 9:55.6 | +69:04 | Sb | 6.93 | 25.7x14.1 | 95 |
M82 | NGC 3034 | 9:55.8 | +69:41 | Pec | 8.41 | 11.2x4.6 | 388 |
Holm. IX | UGC 5336 | 9:57.5 | +69:03 | Im | 15.5 | 1.2x0.5 | 175 |
NGC 3077 | H I.286 | 10:03.3 | +68:44 | E2p | 9.85 | 4.6x3.6 | 148 |
M81 dw B | UGC 5423 | 10:05.5 | +70:22 | Ir+ | 14.94p | 1.2x0.9 | 479 |
IC 2574 | 10:28.4 | +68:25 | S+ | 10.56 | 12.3x5.9 | 185 |
Key: Name, Name II: Some catalog number or name for primary and secondary identification; RA/Dec: Position 2000.0; type: Hubble type; m_v: apparent visual magnitude; dim: dimension in arc minutes; RV: radial velocity (all data from the Sky Catalog 2000.0 when available).
Last Modification: 1 Jul 2001, 23:10 MET