RATAN-600 multi-frequency measurements of the gamma-ray blazar BL Lacertae

ATel #4600; M. Mingaliev, S. Trushkin, J. Sotnikova, A. Erkenov, T. Mufakharov (SAO RAS)
on 22 Nov 2012; 13:58 UT
Credential Certification: Sergei Trushkin (satr@sao.ru)

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We have measured radio flux densities of BL Lac (B2200+420) with the RATAN-600 radio telescope at 4.8, 7.9, 11.2 and 21.7 GHz during 6 October - 20 November, 2012 to study the detected (ATel #4557, #4565, and #4568) flare. In the rest of October BL Lac became bright in X-ray, FIR, microwave and radio bands. Our data agree with the OVRO radio flux 9.6 Jy at 15 GHz by Hovatta et al. (ATEL #4565) on 7 November. We have measured 5.29 +/- 0.1 Jy at 4.8 GHz, 6.85 +/- 0.2 Jy at 7.9 GHz, 7.27 +/- 0.2 Jy at 11.2 GHz and 7.00 +/- 0.3 Jy at 21.7 GHz on 14 October. On 12 November flux density had notably risen to 8.30 +/- 0.19 Jy at 7.7 GHz, to 9.86 +/- 0.2 Jy at 11.2 GHz and to 11.70 +/- 0.3 Jy at 21.7 GHz. Our further observations show the higher fluxes at high frequencies (20 November): 8.83 +/- 0.34 Jy at 7.7 GHz, 11.19 +/- 0.39 Jy at 11.2 GHz and 12.6 +/- 0.6 Jy at 21.7 GHz. Growth of the flux densities has been detected after 15 November at all frequencies, meanwhile the flaring event began during MJD56225-56230 probably. The spectral index changed from -0.08 +/- 0.02 to +0.23 +/- 0.02 at 11.2-21.7 GHz for October to November flux points. The mean spectra in October and November 2012 and the updated light curves are accessed: http://www.sao.ru/hq/giag/new1-en.html