Fermi-LAT spectral analysis of Fermi, Planck, Swift and radio selected samples of AGN

TL;DR

This study analyzes multi-frequency data from Fermi, Planck, Swift, and radio observations to understand the emission mechanisms of various samples of radio-loud AGN, including blazars, across the electromagnetic spectrum.

Contribution

It provides a comprehensive spectral analysis of four well-defined AGN samples using simultaneous multi-frequency data, highlighting new insights into their emission properties.

Findings

Spectral energy distributions characterized for each AGN sample.

Correlation between gamma-ray and radio emissions observed.

Methodology for multi-frequency spectral analysis established.

Abstract

Blazars are jet-dominated extragalactic objects characterized by the emission of strongly variable non-thermal radiation across the entire electromagnetic spectrum. Therefore, the study of blazars (and in general of radio loud AGN) through the use of multi-frequency simultaneous data is essential in order to understand the physical processes that take place in these objects. With Planck, Fermi and Swift simultaneously on orbit, complemented with other space and ground-based observatories, it is possible to assemble high-quality multi-frequency simultaneous broad-band spectra of large and statistically well-defined samples of radio-loud AGN. In particular, four samples of sources have been selected. The first three samples are flux limited in the high energy part of the electromagnetic spectrum: the soft X-ray (0.1-2 keV) sample includes 43 sources from the Rosat All Sky Survey Bright Source Catalog, the hard X-ray (15-150 keV) sample includes 34 sources from the Swift-BAT 54 months source catalog and the gamma-ray sample includes 50 sources from the Fermi-LAT 3 months Bright AGN Source List. The fourth sample is radio flux limited, including 104 bright northern and equatorial radio-loud AGN (most of which have been monitored at Metsahovi Radio Observatory for many years) with average radio flux density at 37 GHz greater than 1 Jy. We present the methods applied and the results of the analysis performed using Fermi-LAT data for all sources in the four different samples of AGN.