Main   Publications   Seminars   Personnel
  SAO RAN   RATAN-600

     

Projects:

 GPS radio sources 
  North Celestial Pole
  BL Lacertae objects

 Group of Active Galactic Nuclei investigation


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

We have measured radio flux densities of BL Lacertae ( 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, mm 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 +/- 0.09 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.

Figure 1.

Growth of the flux densities has been detected after 15 November at all frequencies, meanwhile the flaring event began during MJD56225-56230 probably ( see the light curves and mean spectra in October and November 2012, Figure 1 and 2 ). 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.


Figure 2.