We review the statistical properties of the main populations of radio sources, as emerging
from radio and millimeter sky surveys. Recent determinations of local luminosity functions …

Hierarchical assembly models predict a population of supermassive black hole (SMBH)
binaries. These are not resolvable by direct imaging but may be detectable via periodic …

This paper presents light curves as well as the first systematic characterization of variability
of the 106 objects in the high-confidence Fermi Large Area Telescope Bright AGN Sample …

Photometric measurements are prone to systematic errors presenting a challenge to low-
amplitude variability detection. In search for a general-purpose variability detection …

We present the results of a long-term periodicity search in a sample of γ-ray blazars within a
multiwavelength context. These blazars have been selected from the Steward Observatory …

The ensemble variability properties of nearly 23,000 quasars are studied using the Palomar-
QUEST Survey. The survey has covered 15,000 deg 2 multiple times over 3.5 years using …

ABSTRACT The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space
Telescope discovered a rapid (∼ 5 days duration), high-energy (E> 100 MeV) gamma-ray …

Aims. We have studied the flare characteristics of 55 AGN at 8 different frequency bands
between 4.8 and 230 GHz. Our extensive database enables us to study the various …

Aims. We present a study of variability time scales in a large sample of Active Galactic Nuclei
at several frequencies between 4.8 and 230 GHz. We investigate the differences of various …

We present new, simultaneous, multifrequency observations of 45 out of the 55 candidate
High Frequency Peakers (HFP) selected by Dallacasa et al.([CITE]), carried out 3 to 4 years …