TELAMON Radio Observations of Compact Radio Sources in the Field of IceCube-220625A
ATel #15490; Matthias Kadler (JMU Wuerzburg), Florian Eppel (JMU Wuerzburg), Jonas Hessdoerfer (JMU Wuerzburg), Florian Roesch (JMU Wuerzburg), Philip Weber (JMU Wuerzburg) for the TELAMON Team and Yuri A. Kovalev (ASC Lebedev)
on 1 Jul 2022; 10:55 UT
Credential Certification: Matthias Kadler (matthias.kadler@astro.uni-wuerzburg.de)
Subjects: Radio, Neutrinos, AGN, Blazar
The TELAMON program is using the Effelsberg 100-m telescope of the MPIfR (Max-Planck-Institut fuer Radioastronomie) to monitor the radio spectra of active galactic nuclei (AGN) under scrutiny in astroparticle physics, namely TeV blazars and candidate neutrino-associated AGN.
On June 26, 2022, and June 29, 2022, we have observed eleven compact radio sources listed in the rfc_2021d_catalog that are within a 360 arcmin radius around the best-localization position of the recently detected high-energy neutrino IceCube-220625A (ATel #15472). These are all RFC sources in this field that are associated with known gamma-ray emitting AGN listed in the 4FGL catalog (4FGL-DR3; arXiv:2201.11184; The Fermi-LAT collaboration 2020, ApJS, 247, 33). All but one source are detected at flux densities near their historical (low-frequency) RFC levels. Only one source exceeds its historical maximum: J1207-0106 (Gaia15abj, 4FGL J1207.7-0106) was found on June 29, 2022, with a strongly inverted radio spectrum, raising from 567+-22mJy at 2cm to 614+-34mJy at 1.4cm and 930+-120mJy at 7mm. For comparison, historical flux densities of this source listed in the RFC catalog and in the NED data base between 15GHz and 40GHz range from 100mJy to 350mJy. Also, historic measurements of this source within the RATAN-600 program find only flat spectra up to 0.3Jy.
