BL Lacertae objects

Closest radio galaxy in the Constellation Centaurus

active galactic nucleus with rapid and large-amplitude flux variability and significant optical polarization and with spectrum dominated by a featureless nonthermal emission continuum

BL Lac object in the constellation Cancer

active galaxy, prototype of the BL Lacertae objects

Closest Blazar to the Milky Way

galaxy with a spectrum extending to the highest gamma rays

Blazar TXS 0506+056, first known source of cosmic neutrinos

galaxy in the constellation Piscis Austrinus