Six spiral galaxies lacking dark matter.

Dark matter is believed to be the essential building blocks of galaxy formation. While instances of galaxies lacking dark matter have been observed, these occurrences are typically linked to specific formation mechanisms, making them stand out as unique cases. In spiral galaxies, the presence of flat rotation curves is a common observation, indicating the need for dark matter to support these dynamics.

Discovery of a very Lyman-α-luminous quasar at z = 6.62.

Distant luminous quasars provide important information on the growth of the first supermassive black holes, their host galaxies and the epoch of reionization. The identification of quasars is usually performed through detection of their Lyman-α line redshifted to 0.9 microns at z > 6.