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TANAMI: tracking active galactic nuclei with austral milliarcsecond interferometry: II. additional sources


Mueller, C and Kadler, M and Ojha, R and Schulz, R and Truestedt, J and Edwards, PG and Ros, E and Carpenter, B and Angioni, R and Blanchard, J and Boeck, M and Burd, PR and Doerr, M and Dutka, MS and Eberl, T and Gulyaev, S and Hase, H and Horiuchi, S and Katz, U and Krauss, F and Lovell, JEJ and Natusch, T and Nesci, R and Phillips, C and Ploetz, C and Pursimo, T and Quick, JFH and Stevens, J and Thompson, DJ and Tingay, SJ and Tzioumis, AK and Weston, S and Wilms, J and Zensus, JA, TANAMI: tracking active galactic nuclei with austral milliarcsecond interferometry: II. additional sources, Astronomy & Astrophysics, 610 Article A1. ISSN 1432-0746 (2018) [Refereed Article]

Copyright Statement

Copyright ESO 2018

DOI: doi:10.1051/0004-6361/201731455


Context. TANAMI is a multiwavelength program monitoring active galactic nuclei (AGN) south of - 30degree declination including high-resolution very long baseline interferometry (VLBI) imaging, radio, optical/UV, X-ray, and γ-ray studies. We have previously published first-epoch8.4 GHz VLBI images of the parsec-scale structure of the initial sample. In this paper, we present images of 39 additional sources. The full sample comprises most of the radio- and γ-ray brightest AGN in the southern quarter of the sky, overlapping with the region from which high-energy (> 100 TeV) neutrino events have been found.

Aims. We characterize the parsec-scale radio properties of the jets and compare them with the quasi-simultaneous Fermi/LAT γ-ray data. Furthermore, we study the jet properties of sources which are in positional coincidence with high-energy neutrino events compared to the full sample. We test the positional agreement of high-energy neutrino events with various AGN samples.

Methods. TANAMI VLBI observations at 8.4 GHz are made with southern hemisphere radio telescopes located in Australia, Antarctica, Chile, New Zealand, and South Africa.

Results. Our observations yield the first images of many jets below - 30degree declination at milliarcsecond resolution. We find that γ-ray loud TANAMI sources tend to be more compact on parsec-scales and have higher core brightness temperatures than γ-ray faint jets, indicating higher Doppler factors. No significant structural difference is found between sources in positional coincidence with high-energy neutrino events and other TANAMI jets. The 22 γ-ray brightest AGN in the TANAMI sky show only a weak positional agreement with high-energy neutrinos demonstrating that the > 100 TeV IceCube signal is not simply dominated by a small number of the γ-ray brightest blazars. Instead, a larger number of sources have to contribute to the signal with each individual source having only a small Poisson probability for producing an event in multi-year integrations of current neutrino detectors.

Item Details

Item Type:Refereed Article
Keywords:galaxies: active, galaxies: jets, galaxies: nuclei, radio continuum: galaxies, techniques: high angular resolution, neutrinos
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Lovell, JEJ (Dr Jim Lovell)
ID Code:152741
Year Published:2018
Web of Science® Times Cited:6
Deposited By:Research Performance and Analysis
Deposited On:2022-08-23
Last Modified:2022-11-25

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