Multifrequency quasi-simultaneous observations of six low-synchrotron peaked blazars

We made an estimation of the synchrotron peak frequency (ν peak s ) of the spectral energy distribution (SED) for six blazars. These objects were selected as very-low-synchrotron peaked (VLSP) blazar candidates (with ν peak s ≤ 1013 Hz).We have built the SED of the studied objects using quasi-simultaneous observations on the SAO RAS Zeiss-1000 and RATAN-600 telescopes and made an estimation of the synchrotron peak frequency. As a result, three sources (PKS0446+11, [HB89] 1308+326, and 3C345) were confirmed as VLSP, for the three remaining blazars the calculations have shown ν peak s > 1013 Hz.