Simultaneous spectra and radio properties of BL Lac's

Abstract

We present the results of nine years of the blazar observing programme at the RATAN-600 radio telescope (2005-2014). The data were obtained at six frequency bands (1.1, 2.3, 4.8, 7.7, 11.2, 21.7 GHz) for 290 blazars, mostly BL Lacs. In addition, we used data at 37 GHz obtained quasi-simultaneously with the Metsahovi radio observatory for some sources. The sample includes blazars of three types: high-synchrotron peaked (HSP), low-synchrotron peaked (LSP), and intermediate-synchrotron peaked (ISP). We present several epochs of flux density measurements, simultaneous radio spectra, spectral indices and properties of their variability. The analysis of the radio properties of different classes of blazars showed that LSP and HSP BL Lac blazars are quite different objects on average. LSPs have higher flux densities, flatter spectra and their variability increases as higher frequencies are considered. On the other hand, HSPs are very faint in radio domain, tend to have steep low frequency spectra, and they are less variable than LSPs at all frequencies. Another result is spectral flattening above 7.7 GHz detected in HSPs, while an average LSP spectrum typically remains flat at both the low and high frequency ranges we considered.

14 pages, 6 figures. Accepted for publication in Astronomische Nachrichten

References in corpus (8)

• Roma-BZCAT: A multifrequency catalogue of Blazars
• The 5th edition of the Roma-BZCAT. A short presentation
• Photohadronic origin of $\gamma$-ray BL Lac emission: implications for IceCube neutrinos
• The properties of extragalactic radio sources selected at 20 GHz
• Multi-frequency monitoring of gamma-ray loud blazars: I. Light curves and spectral energy distributions
• RATAN-600 multi-frequency data for the BL Lac objects
• Origin of the Counter-Rotating Gas in NGC 1596
• Multi-frequency spectral analysis of extragalactic radio sources in the 33-GHz VSA catalogue: sources with flattening and upturn spectrum

Cited by in corpus (9)

• Multi-messenger characterization of Mrk 501 during historically low X-ray and $\gamma$-ray activity
• The RATAN-600 multi-frequency catalogue of blazars -- BLcat
• Flux-density measurements of the high-redshift blazar PSO J047.4478+27.2992 at 4.7 and 8.2 GHz with RATAN-600
• Optical and Radio Variability of the Blazar S4 0954+658
• The radio properties of the OH megamaser galaxy IRAS 02524+2046
• The Detection Rate of Associated \mgii\ Absorption Lines in Quasars Depends on Their Radio Emission
• Multi-wavelength observations of the BL Lac object Fermi J1544-0649: one year after its awakening
• Magnetically Driven Relativistic Jet in the High-Redshift Blazar OH~471
• Radio properties of high-redshift galaxies at $z\ge 1$