Multi-frequency monitoring of gamma-ray loud blazars: I. Light curves and spectral energy distributions

TL;DR

This study presents a comprehensive multi-frequency monitoring campaign of 35 blazars, providing extensive radio, near-IR, and optical data to analyze their spectral energy distributions and variability patterns over 18 months.

Contribution

It offers a large, contemporaneous multi-frequency dataset of blazars, enabling detailed analysis of their spectral energy distributions and variability, which is valuable for understanding jet physics.

Findings

Most sources show significant variability across all bands.

Constructed SEDs for well-sampled sources during the first 18 months.

Collected about 4000 radio and 5500 near-IR and optical measurements.

Abstract

Context: Being dominated by non-thermal emission from aligned relativistic jets, blazars allow us to elucidate the physics of extragalactic jets, and, ltimately, how the energy is extracted from the central black hole in radio-loud active galactic nuclei. Aims: Crucial information is provided by broad-band spectral energy distributions (SEDs), their trends with luminosity and correlated multi-frequency variability. With this study we plan to obtain a database of contemporaneous radio-to-optical spectra of a sample of blazars, which are and will be observed by current and future high-energy satellites. Methods: Since December 2004 we are performing a monthly multi-frequency radio monitoring of a sample of 35 blazars at the antennas in Medicina and Noto. Contemporaneous near-IR and optical observations for all our observing epochs are organised. Results: Until June 2006 about 4000 radio measurements and 5500 near-IR and optical measurements were obtained. Most of the sources show significant variability in all observing bands. Here we present the multi-frequency data acquired during the first eighteen months of the project, and construct the SEDs for the best-sampled sources.