Some of these objects have gaps in their ultraviolet spectrum due to the existence of neutral hydrog
Some of these objects have gaps in their ultraviolet spectrum due to the existence of neutral hydrogen in the intergalactic medium,  providing evidence for the reionization of hydrogen around z = 6. Gravitational lensing was first confirmed by a twin of these. These objects can have redshifts greater than 5.8, which is where the (*) Gunn-Peterson trough is observed. Their variability suggests they are compact, of a size on the order of light-weeks or months. These objects are powered by accretion disks around supermassive black holes. For 10 points, name these remnants of the early universe which emit as much energy as some galaxies, are the most luminous objects in the universe, and are composed mostly of "radio quiet" types.
Some of these objects have gaps in their ultraviolet spectrum due to the existence of neutral hydrogen in the intergalactic medium,  providing evidence for the reionization of hydrogen around z = 6.
{quasi}-{stellar} radio {sources} [or {Quasi}-{Stellar} Objects; or {quasars}]