SIZING UP GALAXIES
Most of the largest structures are elliptical, but there are some notable exceptions
1 Milky Way
Size of galaxy:
100,000 light years Type of galaxy:
Barred spiral
2 Messier 87
Distance: 54 million light years
Size of galaxy: 120,000 light years Type of galaxy: Elliptical
The closest giant elliptical to us has a monster black hole at its heart and an active galactic nucleus thanks to a recent merger. However, its extended outer halo of stars seems to have been truncated by the influence of other nearby galaxies.
3 UGC 1382
Distance: 250 million light years Size of galaxy: 718,000 light years Type of galaxy: Spiral
Astronomers discovered this rare ‘Frankenstein galaxy’ in the constellation of Cetus. Originally assumed to be an ancient elliptical, ultraviolet and radio images revealed the presence of tenuous spiral arms and huge gas clouds, probably cannibalised from other galaxies.
4 NGC 1275
Distance: 237 million light years
Size of galaxy: 100,000 light years Type of galaxy: Elliptical
The central cD galaxy of the Perseus Cluster, NGC 1275 has an active galactic nucleus and is also known as the radio source Perseus A. Seen from Earth, another dusty galaxy lies directly in front of it, falling towards the cD galaxy on a collision course.
5 IC 1101
Distance: 1.04 billion light years
Size of galaxy: 4 million light years Type of galaxy: Elliptical or lenticular IC 1101 is often described as the largest known galaxy in the universe. Its extended outer halo of stars suggests it is a cD galaxy, but some astronomers suspect the halo is actually a face-on disc, making it a lenticular instead.
6 NGC 1399
Distance: 66 million light years
Size of galaxy: 130,000 light years Type of galaxy: Elliptical
Like Messier 87, NGC 1399, the central galaxy of the nearby Fornax Cluster, is surrounded by a large number of globular clusters – around 6,000 – revealing a long and ancient history of galactic mergers and starbursts.
7 NGC 4889
Distance: 308 million light years Size of galaxy: 250,000 light years Type of galaxy: Elliptical
One of two supergiant elliptical galaxies that anchor the Coma Cluster, NGC 4889 is home to a central black hole that contains a staggering 21 billion solar masses of material.
8 NGC 5128
Distance: 13 million light years
Size of galaxy: 80,000 light years Type of galaxy: Elliptical/lenticular This is a nearby example of a merger in action and a galaxy on its way to becoming a giant elliptical. Seen in visible light, the dust from a foreground spiral forms a dark lane across the larger lenticular galaxy.
9 NGC 6872
Distance: 212 million light years Size of galaxy: 522,000 light years Type of galaxy: Barred spiral
One of the biggest spiral galaxies, thanks to its elongated arms. They have probably unwound into their shape under the influence of tidal forces from a much smaller nearby lenticular galaxy, known as IC 4970.