Correlation between Fermi/LAT gamma-ray and 37 GHz radio properties of northern AGN averaged over 11 months

: Nieppola E, Tornikoski M, Valtaoja E, Leon-Tavares J, Hovatta T, Lahteenmaki A, Tammi J

: F Combe

Publisher: EDP SCIENCES S A

: 2011

Astronomy and Astrophysics

: Astronomy & Astrophysics

: ASTRONOMY & ASTROPHYSICS

: ASTRON ASTROPHYS

: ARTN A69

: 535

: 12

: 0004-6361

DOI: https://doi.org/10.1051/0004-6361/201116818

Results. We find significant correlation between both the flux densities and luminosities in gamma and radio bands. The Fermi luminosity is inversely correlated with the peak frequency of the synchrotron component of the AGN spectral energy distributions. We also calculate the gamma dominances, defined as the ratio between the gamma and radio flux densities, and find an indication that high-energy blazars are more gamma-dominated than low-energy blazars. After studying the distributions of gamma and radio luminosities, it is clear that BL Lacertae objects are different from quasars, with significantly lower luminosities. It is unclear whether this is an intrinsic difference, an effect of variable relativistic boosting across the synchrotron peak frequency range, or the result of Fermi being more sensitive to hard spectrum sources like BL Lacertae objects. Our results suggest that the gamma radiation is produced co-spatially with the 37 GHz emission, i.e., in the jet.