the biggest galaxy in the universe

IC 1101 the biggest galaxy we've found in the universe! it lives 1 billion light years away (at z = 0.0767) in the massive abell 2029 galaxy cluster. the unromantic name comes from the index catalogue which was created at the end of the 19th century.

IC 1101 floats with a girth of 6 million light years, making it 60 times larger than our milky way with its mere 100,000 light year diameter. how many stars does the most massive elliptical galaxy contain? 100,000,000,000,000 = 100 trillion = 10^14 stars. how does the number of stars in the largest galaxy in the universe compare to the number of cells in the human body? see starts with a bang to find out!


the above right image shows the entire abell 2029 cluster in optical light from the digitized sky survey. IC 1101 is the big bright one living right at the center. the left image shows what the cluster looks like in x-ray light, as seen by the chandra telescope. the optical views shows lots of individual galaxies floating around the biggest concentration of mass that sits right at the center. the x-ray light is created by very very hot gas. the image shows a smooth distribution of multi-million degree gas, concentrated at the center of the cluster, but extending far out into the outer regions! here's another optical image...


one thing i wonder... why is this the most massive galaxy in the universe? why dont galaxies get bigger? there are several galaxies at the centers of different clusters that are close to this big, but what creates an upper limit on the mass of a galaxy? (and the dark matter halo that it lives in?) basically, the limits are set by the initial distribution of matter after the big bang, time, and the expansion of the universe, but... i still wonder.