Fanaroff-Riley Type I
Fanaroff-Riley Type I (FR I) galaxies are a classification of radio galaxies characterized by their low surface brightness and large radio lobes. These lobes are often found extending far from the central active galactic nucleus, which is typically a supermassive black hole. The radio emissions in FR I galaxies are primarily due to the synchrotron radiation from relativistic electrons.
In FR I galaxies, the jets of plasma emitted from the central region are weak and become disrupted as they travel through the intergalactic medium. This results in a more diffuse and less structured appearance compared to Fanaroff-Riley Type II (FR II) galaxies, which have stronger, more collimated jets.