The Maffei group is a famous nearby group of galaxies even though most of the galaxies in the group have only been discovered in the past twenty years. A lot of the galaxies in this group lie directly behind the plane of our galaxy and are hidden by all the intervening gas, dust and stars. Only the left side of this group around the nearby IC 342 galaxy is easily visible - most of the galaxies around Maffei I and II were not discovered until the 1990's.
Below - three very obscured galaxies. Maffei I (left) is the nearest large elliptical galaxy. Maffei II (centre) is a spiral galaxy with a prominant bar at the centre of it. Dwingeloo 1 (right) is a barred spiral galaxy at the back of the group but it is so faint that it was not discovered until 1994. The foreground dust in our galaxy blocks most of the blue light from these galaxies and makes them look much more red than they actually are.
 |
 |
 |
| Maffei I | Maffei II | Dwingeloo 1 |
This is a list of the main galaxies in the Maffei group. A lot of the diameters of these galaxies are only rough estimates because most of these galaxies are very obscured. The dominant galaxies in this group are IC 342, Maffei I and Maffei II.
1 2 3 4 5 6 7 8 9
Name Equatorial Blue Type Size Size RV Other
Coordinates Mag (') kly km/s Names
RA Dec
Cas 3 01 07.5 +51 26 17.1 Irr 1 5 -166 KKH5
KKH6 01 34.9 +52 06 17.0 Irr 1 5 -141
Cas 1 02 06.1 +69 01 16.4 Irr 5.5 10 -95 KK19
Perseus 1 02 24.6 +56 01 16.2 Irr 2.2 5 -93 KKH11
Perseus 2 02 27.4 +57 29 17.8 Irr 3.4 10 -90 KKH12
UGC 2773 02 32.1 +47 48 14.3 Irr 1.2 5 +83 KK28
MB 1 02 35.6 +59 23 19.5 Irr 1.9 5 +39 KK21
Maffei 1 02 36.6 +59 39 14.4 E 18.2 55 -138 UGCA 34
MB 2 02 37.0 +59 14 ? Irr? ? ? ?
Maffei 2 02 41.9 +59 36 16.0 SBbc 21.4 60 -134 UGCA 39
Dwingeloo 2 02 54.1 +59 00 20.5 Irr 5.4 20 -47
MB 3 02 55.7 +58 52 19.8 E 3.9 10 -43 KK22
Dwingeloo 1 02 56.9 +58 55 17.7 SBcd 8.0 35 -28 Cas 2
KK35 03 45.2 +67 52 ? Irr ? ? +32
IC 342 03 46.8 +68 06 9.2 Sc 36.3 75 -62
UGCA 86 03 59.8 +67 08 14.2 Sm 10.2 20 -12
Cam A 04 25.3 +72 48 14.9 E 3.1 10 -192 KK41
NGC 1569 04 30.8 +64 51 11.7 Irr 5.8 10 -153
NGC 1560 04 32.8 +71 53 12.1 Scd 11.5 35 -94
UGCA 92 04 32.1 +63 37 16.1 Irr 4.4 10 -164
Cam B 04 53.1 +67 06 16.7 Irr 2.6 5 +27 KK44
UGCA 105 05 14.2 +62 35 13.2 Sm 7.4 20 +76
Cam D 05 59.7 +73 26 17.1 Irr 1 5 +93 KKH34
Mailyan 16 06 47.8 +80 07 16.4 Irr 1 5 -157 KKH37
|
Column 1: The usual name of the galaxy.
Column 2: The Right Ascension for epoch 2000.
Column 3: The Declination for epoch 2000.
Column 4: The blue apparent magnitude of the galaxy.
Column 5: The galaxy type: E=Elliptical, S0=Lenticular, Sa,Sb,Sc,Sd=Spiral,
SBa,SBb,SBc,SBd=Barred Spiral, Sm,SBm,Irr=Irregular.
Column 6: The angular diameter of the galaxy (arcminutes).
Column 7: The diameter of the galaxy (thousands of light years).
Column 8: The recessional velocity (km/s) of the galaxy relative to
the cosmic microwave background.
Column 9: Other names of the galaxy.
References:
Huchtmeier W, Westpfahl D, Karachentsev I, Karachentseva V, (2001), The IC342/Maffei
Group of Galaxies. Gas and Galaxy Evolution ASP Conf Ser 240, 589.
Buta R, McCall M, (1999), The IC342/Maffei Group Revealed. Astrophys J Supp, 124, 33.
Karachentsev I, Makarov D, Huchtmeier W, (1999) HI properties of nearby galaxies
from a volume-limited sample. Astron Astrophys Suppl, 139, 97.
Schmidt K, Priebe A, Boller T, (1993), Nearby Galaxies. Astron Nachr, 314, 371.
The HyperLeda Database, (2003).
The two Maffei galaxies were discovered by Paolo Maffei in 1968. He noticed an Infrared Object in the Region of IC 1895 and he suggested that there might be obscured galaxies in this region. The two galaxies had previously been catalogued as emission nebulae - Stewart Sharpless listed them as objects 191 and 197 in his Catalogue of H II Regions published in 1959.
Between 1971 and 1973, two groups ( 1, 2) lead by Hyron Spinrad confirmed that Maffei I and II were galaxies and they suggested that Maffei I might be a member of the Local Group. They were wrong, but it is not unusual to see reference books describe Maffei I as a Local Group galaxy.
The announcement of a third major galaxy was made by Kraan-Korteweg, Loan, Burton, Lahav, Ferguson, Henning and Lynden-Bell in 1994. The galaxy was discovered using the Dwingeloo 25m radio telescope in the Netherlands and so was named Dwingeloo 1. A small companion galaxy - Dwingeloo 2 - was discovered shortly afterwards.
For an excellent survey (published in 1999) of many of the galaxies in this group see: The IC 342/Maffei Group Revealed by Ronald Buta and Marshall McCall.
Shown below are three other galaxies in this group. NGC 1560 (left) is a spiral or irregular galaxy viewed edge-on. NGC 1569 (centre) is only a dwarf galaxy but it is probably the nearest example of a starburst galaxy - a galaxy which is rapidly forming a lot of new stars. UGCA 105 (right) is a dwarf galaxy with vague signs of spiral structure.
 |
 |
 |
| NGC 1560 | NGC 1569 | UGCA 105 |
Below is a picture of IC 342. This is probably the largest galaxy in the Maffei group. If it was not so close to the plane of the Milky Way, it would probably be one of the most famous galaxies in the sky. (It would possibly be a naked-eye object). This galaxy was not discovered until about 1890 because it is rather obscured by the foreground dust and stars in our own galaxy, but it is still a spectacular galaxy.
Below - three dwarf irregular galaxies in the Maffei group. UGC 2773 (left) is a compact dwarf galaxy located at the back of the group. UGCA 86 (centre) and UGCA 92 (right) are much closer, they are two faint irregular dwarf galaxies located about seven million light years from us at the front of the group near IC 342.
 |
 |
 |
| UGC 2773 | UGCA 86 | UGCA 92 |
| Properties of the Maffei Group | |
|---|---|
| Equatorial Coordinates | RA=03h30m Dec=+60° |
| Galactic Coordinates | l=140° b=+5° |
| Supergalactic Coordinates | L=5° B=-5° |
| Distance to the centre of the group | 10 million light years |
| Number of large galaxies | 5 |
| Alternative names for the group | IC 342 Group |
