Active Galactic Nuclei (AGN) are characterized by a strong emission coming from a very compact region (only few pcs) at the galaxy center. Blazars form a class of AGN, characterized by high luminosity in a broad frequency range, from radiofrequencies to high energies (X-rays and γ -rays), as well as extreme variability and high polarization at

In addition to being a long-postulated particle that satisfactorily explains the absence of the neutron’s dipole moment observed in laboratories while addressing the charge-parity problem in quantum chromodynamics, the axion emerges as a promising dark matter candidate due to its low mass and weak interaction with ordinary matter. Dark matter is a

Keeping the Observatorios de Canarias (OOCC) among the most competitive sites in the World for astronomical observation requires a continuous effort to characterize the conditions of the atmosphere above them. The techniques and instrumentation must be on the state of the art, appropriate parameters must be identified, and measurements must be