Radio Flaring of the Quasar Ton 599 (4C +29.45) on Historical Levels
ATel #15872; F. Eppel (University of Wurzburg), J. Hessdoerfer (University of Wurzburg), M. Kadler (University of Wurzburg), P. Benke (MPIfR Bonn), A. Gokus (Washington University St. Louis), S. Haemmerich (ECAP/Remeis-Observatory Bamberg), D. Kirchner (University of Wurzburg), F. Roesch (University of Wurzburg), J. Sinapius (DESY Zeuthen), P. Weber (University of Wurzburg) for the TELAMON Team
on 24 Jan 2023; 06:30 UT
Credential Certification: Matthias Kadler (matthias.kadler@astro.uni-wuerzburg.de)
Subjects: Radio, AGN, Blazar, Quasar
We report radio flaring activity of the flat-spectrum radio quasar Ton 599 (4C +29.45) at high radio frequencies in the 14mm and 7mm bands observed as part of the TELAMON program. We have been monitoring the source continuously since mid 2022 and found a monotonic rise in radio flux density since July 2022. During the low-state on July 9, 2022 we have observed a flux density of (2.28 ± 0.10 Jy) at 14mm and (1.82 ± 0.13 Jy) at 7mm. The most recent flux density levels on Jan 19/20, 2023 are now reaching (6.731 ± 0.071) Jy and (6.73 ± 0.14) Jy at 14mm and 7mm, respectively (all values averaged over four frequencies within each band). This corresponds to an increase in flux density by more than a factor of three in about six months and is comparable to historical maximum flux densities reported for this source at similar frequencies.
The radio flaring seems to correlate with an ongoing multi-waveband flare of this source reported in the optical, X-ray and gamma-ray bands (Atel #15859, #15854, #15853, #15870).
The TELAMON program uses the Effelsberg 100-m telescope to monitor the radio spectra of very-high-energy emitting active galactic nuclei (AGN), namely TeV blazars and candidate neutrino-associated AGN, with high-cadence high-frequency observations every ~3 weeks and at multiple frequencies up to 44 GHz.
We will continue monitoring the source regularly and encourage more observations especially at other wavelengths to further characterize the multiwavelength flaring event in this TeV-detected (Atel #11075) blazar.of
