Australia Telescope Compact Array radio monitoring of gamma-ray emitting AGN

As Australia’s national science agency and innovation catalyst, CSIRO is solving the greatest challenges through innovative science and technology. CSIRO. Unlocking a better future for everyone. Australia Telescope Compact Array radio monitoring of gamma-ray emitting AGN Australia Telescope Compact Array radio monitoring of gamma-ray emitting AGN We are conducting a long-running, multi-frequency, flux density monitoring program using the Australia Telescope Compact Array (ATCA) [1] as part of the TANAMI project [2]. The majority of bright gamma-ray AGN are also bright, and variable, radio sources, and studies of the correlations between variability can help determine the origin, and hence physical mechanism, for the gamma-ray production. ATCA monitoring is undertaken in the 4cm, 1cm, and 7mm radio bands to study the timeand spectral-evolution of AGN. Radio observations provide a range of time resolutions from rapid flares to slower changes over months to years. The core of the program is a set of ∼180 AGN, primarily Fermi-detected gamma-ray sources, with about thirty TeV gamma-ray sources and 10 candidate neutrino associations rounding out the current source list. The pipe-line processed data are made publicly available shortly after the observations at https://www.narrabri.atnf.csiro.au/calibrators/ . Philip Edwards1,* , Jamie Stevens1, Roopesh Ojha2, Matthias Kadler3, Gavin Rowell4, Xi Shao5,1 1. CSIRO 2. NASA 3. Julius Maximilians University Würzburg 4. University of Adelaide 5. Shanghai Astronomical Observatory * [email protected] An example of ATCA monitoring for one source is shown in the figure, with the Fermi light-curve below. The prominent gamma-ray outburst in 2021/21 is accompanied (and possibly even preceded) by a radio outburst. However, the radio flare around 2010 was not associated with any gamma-ray activity, and the gamma-ray flaring around 2015 saw only a marginal increase in radio flux densities. Collaborations to help explain these observations are welcomed! And the first 10 people to correctly identify the source will win a chocolate J The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Gomeroi people as the Traditional Owners of the Observatory site. References [1] Stevens et al. 2012, arXiv:1205.2403 [2] Kadler et al. 2015, AN, 336, 499