Blazars are active galactic nuclei (AGN) associated with a supermassive black hole in the nucleus of its host galaxy. Their characteristic is the emission of a jet of plasma moving at a relativistic speed along our line of sight.

A recent work, coordinated by Claudia M. Raiteri (in collaboration with various authors, including Massimo Villata, Maria Isabel Carnerero and Barbara Balmaverde from OATo), investigates the brightness variability in a blazar called S50716 + 714, using the Transiting Exoplanet Survey Satellite (TESS) space telescope.

The researchers analyzed the light curve, that is the variation of the source brightness as a function of time, with a time resolution of 2 minutes, also using photometric observations of various telescopes around the world participating in the Whole Earth Blazar Telescope (WEBT) network.
They found that the variability with time scales below about 5 hours is probably related to substructures of the jet; on the other hand, variability with longer time scales (greater than 12 hours) is likely due to small variations in the jet orientation with respect to the line of sight.
The paper “The dual nature of blazar fast variability: Space and ground observations of S5 0716+714” by Raiteri C. M. et al. has been published in Monthly Notices of the Royal Astronomical Society.

Rappresentazione artistica di un blazar

Credit: M. Weiss/CfA