1-37 GHz quasi-simultaneous spectrum of the blazar Ton 599 (4C +29.45) during its greatest radio flare
ATel #15894; Mufakharov T. (SAO RAS), Mikhailov A. (SAO RAS), Kovalev Yu. (ASC Lebedev), Volvach A. (CrAO), Sotnikova Yu. (SAO RAS), Mingaliev M. (SAO RAS), Volvach L. (CrAO), Semenova T. (SAO RAS)
on 9 Feb 2023; 21:05 UT
Credential Certification: Alexander Mikhailov (mag10629@yandex.ru)
Subjects: Radio, AGN, Blazar, Quasar
We report the historical high flux density level of the flat-spectrum radio quasar Ton 599 (4C +29.45) at 1.2-36.8 GHz. According to the flaring activity at high radio frequencies (ATel#15872, #15873) the blazar showed its historical maximum of the flux densities at 21-230 GHz in late Jan 2023. The RATAN-600 quasi-simultaneous spectra were measured at six frequencies at four epochs in Jan-Feb 2023. The obtained spectral flux density values for each date at 22.3, 11.2, 8.2, 4.7, 2.3, and 1.2 GHz are as follows.
| Date
| 22.2 GHz
| 11.2 GHz
| 8.2 GHz
| 4.7 GHz
| 2.3 GHz
|
| 28 Jan |
7.77 (0.57) |
6.11 (0.28) |
5.20 (0.20) |
3.49 (0.12) |
2.28 (0.04) |
| 30 Jan |
7.76 (0.60) |
6.29 (0.29) |
5.14 (0.20) |
3.64 (0.13) |
2.40 (0.08) |
| 31 Jan |
8.09 (0.56) |
6.32 (0.31) |
4.91 (0.19) |
3.52 (0.12) |
2.24 (0.05) |
| 08 Feb |
8.25 (0.60) |
6.66 (0.31) |
5.24 (0.20) |
3.77 (0.13) |
1.96 (0.22) |
At 1.2 GHz we measured an average value for four epochs as 1.48 (0.2) Jy. Radio spectrum has a rising shape with a spectral index +0.36 (0.10) at 8.2-22.3 GHz (see the combined spectrum at the link below).
The RT-22 (Simeiz) radio telescope (with a 22-m antenna operated by the Crimean astrophysical observatory of the RAS) measured spectral flux densities of Ton 599 on 15 Jan as 7.58 (0.16) and 7.72 (0.11) Jy at 22.2 and 36.8 GHz, respectively. On 8 Feb the flux densities continued to rise: 8.61 (0.17) and 9.12 (0.13) Jy at these frequencies.
In comparison to earlier RATAN measurements of the Ton 599 its flux densities have grown three times at 22 GHz since 2015-2016 (see www.sao.ru/blcat/). On 24 Dec 2022 the RATAN fluxes were also significantly lower: 4.77 (0.11), 4.49 (0.11), 3.86 (0.13), 3.07 (0.8), 2.10 (0.05), 2.05 (0.64) Jy at 22.3, 11.2, 8.2, 4.7, 2.3, and 1.2 GHz. We will continue monitoring of the source regularly with the RATAN-600 and RT-22 telescopes.
The RATAN-600 simultaneous radio spectra of the Ton 599
