Slug Nebula

The Slug Nebula is one of the largest and most luminous Lyman-alpha nebula discovered so far extending over 450 kpc. The nebula sits at a distance of z=2.283 surrounds a bright quasar named UM287.^[1]

Slug Nebula

Nebula
Image of the Slug Nebula. The bright circular blue-white for is the quasar UM 287 while the blue haze is the nebula itself.
Observation data
Distance	z=2.283
Physical characteristics
Radius	450 kpc pc
Notable features	One of the largest and luminous Lyman-alpha nebula
See also: Lists of nebulae

It has a high surface brightness and is filimentary. This high surface brightness implies two things: (1) very large densities of cold and ionized gas, (2) very large colum densities of neutral hydrogen.^[2]