TELAMON: Effelsberg Monitoring of AGN Jets with Very-High-Energy Astroparticle Emissions -- II. Polarization properties

We present recent results of the TELAMON program, which is using the Effelsberg 100-m telescope to monitor the radio spectra of active galactic nuclei (AGN) under scrutiny in astroparticle physics, namely TeV blazars and neutrino-associated AGN. Our sample includes all known Northern TeV-emitting blazars as well as blazars positionally coincident with IceCube neutrino alerts. Polarization can give additional insight into the source properties, as the polarized emission is often found to vary on different timescales and amplitudes than the total intensity emission. Here, we present an overview of the polarization properties of the TeV-emitting TELAMON sources at four frequencies in the 20 mm and 7 mm bands. While at 7 mm roughly $82\,\%$ of all observed sources are found to be significantly polarized, for 20 mm the percentage is $\sim58\,\%$. We find that most of the sources exhibit mean fractional polarizations of $<5\%$, matching the expectations of rather low polarization levels in these sources from previous studies at lower radio frequencies. Nevertheless, we demonstrate examples of how the polarized emission can provide additional information over the total intensity.Comment: 9 pages, 2 figures, Proceedings of the 38th International Cosmic Ray Conference (ICRC2023

Multi-epoch monitoring of TXS 0506+056 with MAGIC and MWL partners

Funding Information: The Australia Telescope Compact Array is part of the Australia Telescope National Facility 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. Funding Information: The members of the MAGIC Collaboration gratefully acknowledge financial support from the agencies and organizations listed here: https://magic.mpp.mpg.de/acknowledgments_ ICRC2021 This research is partly based on observations with the 100-m telescope of the MPIfR (Max-Planck-Institut für Radioastronomie) at Effelsberg. Funding Information: This research has made use of data from the OVRO 40-m monitoring program which was supported in part by NASA grants NNX08AW31G, NNX11A043G and NNX14AQ89G, and NSF grants AST-0808050 and AST-1109911, and private funding from Caltech and the MPIfR. Publisher Copyright: © Copyright owned by the author(s) under the terms of the Creative Commons.The measurement of an astrophysical flux of high-energy neutrinos by IceCube is an important step towards finding the long-sought sources of cosmic rays. Nevertheless, the long exposure neutrino sky map shows no significant indication of point sources so far. The real-time followup of neutrino events turned out to be the most successful approach in neutrino point-source searches. It brought, among others, the most compelling evidence for a neutrino point source: the flaring gamma-ray blazar TXS 0506+056 in coincidence with a single high-energy neutrino from IceCube (IceCube-170922A). The fast multiwavelength(MWL) follow-up of this alert was key for establishing this coincidence and constraining the subsequent theoretical modeling for this event. In the long run, accurate and contemporaneous MWL spectral measurements are essential ingredients in investigating the physical processes leading to particle acceleration and emission of radiation. A deeper understanding of those processes allows us to put constraintson the potential neutrino emission. Here we present the light curves and simultaneous spectral energy distributions from November 2017 till February 2021 of MAGIC and MWL monitoring of TXS 0506+056. The more than two-year-long rise and high state of the radio light curve of TXS 0506+056, which started near the time of the IceCube neutrino detection, seems to have ended, as indicated by a steep decrease in the first half of 2021. We also present the theoretical interpretation of our observations.Peer reviewe

Multi-epoch monitoring of TXS 0506+056 with MAGIC and MWL partners

The measurement of an astrophysical flux of high-energy neutrinos by IceCube is an importantstep towards finding the long-sought sources of cosmic rays. Nevertheless, the long exposureneutrino sky map shows no significant indication of point sources so far. The real-time follow-up of neutrino events turned out to be the most successful approach in neutrino point-sourcesearches. It brought, among others, the most compelling evidence for a neutrino point source:the flaring gamma-ray blazar TXS 0506+056 in coincidence with a single high-energy neutrinofrom IceCube (IceCube-170922A). The fast multiwavelength(MWL) follow-up of this alert waskey for establishing this coincidence and constraining the subsequent theoretical modeling for thisevent. In the long run, accurate and contemporaneous MWL spectral measurements are essentialingredients in investigating the physical processes leading to particle acceleration and emission of radiation. A deeper understanding of those processes allows us to put constraints on the potentialneutrinoemission. Herewepresentthelightcurvesandsimultaneousspectralenergydistributionsfrom November 2017 till February 2021 of MAGIC and MWL monitoring of TXS 0506+056.The more than two-year-long rise and high state of the radio light curve of TXS0506+056, whichstarted near the time of the IceCube neutrino detection, seems to have ended, as indicated bya steep decrease in the first half of 2021. We also present the theoretical interpretation of ourobservations

Multi-epoch monitoring of TXS 0506+056 with MAGIC and MWL partners

The measurement of an astrophysical flux of high-energy neutrinos by IceCube is an important step towards finding the long-sought sources of cosmic rays. Nevertheless, the long exposure neutrino sky map shows no significant indication of point sources so far. The real-time followup of neutrino events turned out to be the most successful approach in neutrino point-source searches. It brought, among others, the most compelling evidence for a neutrino point source: the flaring gamma-ray blazar TXS 0506+056 in coincidence with a single high-energy neutrino from IceCube (IceCube-170922A). The fast multiwavelength(MWL) follow-up of this alert was key for establishing this coincidence and constraining the subsequent theoretical modeling for this event. In the long run, accurate and contemporaneous MWL spectral measurements are essential ingredients in investigating the physical processes leading to particle acceleration and emission of radiation. A deeper understanding of those processes allows us to put constraints on the potential neutrino emission. Here we present the light curves and simultaneous spectral energy distributions from November 2017 till February 2021 of MAGIC and MWL monitoring of TXS 0506+056. The more than the two year-long rise and high state of the radio light curve of TXS 0506+056, which started near the time of the IceCube neutrino detection, seems to have ended, as indicated by a steep decrease in the first half of 2021. We also present the theoretical interpretation of our observations.ISSN:1824-803