Survey of Data for Determining Scales of the Absolute Flux Densities in 10–180 MHz Range and Source Spectra in the Declination Strip 10°–20°

  • S. Ya. Braude
Part of the International Astronomical Union / Union Astronomique Internationale book series (IAUS, volume 74)

Abstract

To determine the frequency spectra of radio sources the flux densities of these sources should be measured at the widest possible frequency range. The use of different telescope types, methods of measurements and calibrations led in a number of cases to the considerable difference in the data of various observatories. At the present time for frequencies above 400 MHz the scales of flux densities — S for — S ≥ 1 Jy = 10−26w m−2Hz−1 presented by different authors coincide accurate to 5%. Up to now for frequencies below 200 MHz a single scale of fluxes recognized by all radioastronomers is absent. We attempted to determine such a scale for frequencies 180-10 MHz. We used both analysis of the published data and the results of the new measurements obtained with the UTR-2 Radiotelescope in the declination strip 10°–20° at frequencies 10.0; 12.6; 14.7; 16.7; 20, and 25 MHz. The method of these measurements and the obtained results are described in detail in [1]. The UTR-2 Radiotelescope has 5 beams in declination with half power beam width in a zenith direction 20’ × 20’ at 25 MHz [2]. The absolute values of the flux densities of all observed discrete radio sources are defined during the experiments. Minimum flux density measured at frequency 25 MHz — 15–20 Jy, with a signal-to-noise ratio equal to 3–4. During measurements about 300 radio sources were found.

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Copyright information

© International Astronomical Union 1977

Authors and Affiliations

  • S. Ya. Braude
    • 1
  1. 1.Institute of Radio Physics and ElectronicsAcademy of Sciences of the Ukrainian SSRKharkov 85USSR

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