Multifrequency interferometer and radio continuum monitoring observations of CTA 102

Abstract

This paper represents the work of several years of observation of CTA 102 with both single dish telescopes and interferometric arrays, covering wavelengths from 1.2 cm to 1.3 mm. The resolution of the maps covers an order of magnitude from 0.5 mas to 50 μ as. The images presented demonstrate the rapid structural changes in this source. These rapid structural changes correlates with the outbursts seen in the total flux, turnover frequency and in the spectral index. We have calculated the Brightness Temperatures of the components ( T B ) directly from the determined component sizes and also using the logarithmic variability amplitudes and timescales to calculate the $T_{\mathrm{B}}$s. Both the methods yielded measurements of source frame T B s no higher than ~a $\rm few\times 10^{12}$ K. We find that the observed average proper motion is ~$0.4 \pm 0.07$ mas/yr, which corresponds to an apparent transverse velocity of $11 \pm 2$ c.