Radio and Gamma-ray Properties of Extragalactic Jets from the TANAMI Sample

Using high-resolution radio imaging with VLBI techniques, the TANAMI program has been observing the parsec-scale radio jets of southern (declination south of −30◦) gamma-ray bright AGN simultaneously with Fermi /LAT monitoring of their gamma-ray emission. We present the radio and gamma-ray properties of the TANAMI sources based on one year of contemporaneous TANAMI and Fermi /LAT data. A large fraction (72%) of the TANAMI sample can be associated with bright gamma-ray sources for this time range. Association rates differ for different optical classes with all BL Lacs, 76% of quasars and just 17% of galaxies detected by the LAT. Upper limits were established on the gamma-ray flux from TANAMI sources not detected by LAT. This analysis led to the identification of three new Fermi sources whose detection was later confirmed. The gamma-ray and radio luminosities are related by L ∝ L_r^(0.89±0.04). The brightness temperatures of the radio cores increase with the average gamma-ray luminosity, and the presence of brightness temperatures above the inverse Compton limit implies strong Doppler boosting in those sources. The undetected sources have lower gamma/radio luminosity ratios and lower contemporaneous brightness temperatures. Unless the Fermi/LAT-undetected blazars are strongly gamma-ray-fainter than the Fermi /LAT-detected ones, their gamma-ray luminosity should not be significantly lower than the upper limits calculated here.
Bibliographic reference
Böck, M. Kadler, Matthias Müller, C. Tosti, G. Ojha, R. Wilms, J. Bastieri, D. Burnett, T. Carpenter, B. Cavazzuti, E. Dutka, M. Blanchard, J. Edwards, P.G. Hase, H. Horiuchi, S. Jauncey, D.L. Krauss, F. Lister, Matthiew L. Lovell, J.E.J. Lott, B. Murphy, D. W. Phillips, C. Plötz, C. Pursimo, T. Quick, J. Ros Ibarra, Eduardo Taylor, G. Thompson, D. J. Tingay, S. J. Tzioumis, A.K. Zensus, J. Anton 2016 Radio and Gamma-ray Properties of Extragalactic Jets from the TANAMI Sample Astronomy and Astrophysics 590 A40 1 12