I was going through the following paper: https://arxiv.org/pdf/1605.08054.pdf In the 2nd line, it says, "GN-z11, a MUV=-21.1 galaxy at z=11.1." I know, what z=11.1 is. If I'm correct, it's the redshift of the galaxy which helps in measuring its velocity. I'm not quite sure, though, of what MUV is or why the galaxy is named GN-z11. Any help will be highly appreciated. Thanks.