Title: Interferometric Monitoring of Gamma-ray Bright AGNs: S5 0716+714,
Abstract: We present the results of very long baseline interferometry (VLBI)
observations of gamma-ray bright blazar S5 0716+714 using the Korean VLBI
Network (KVN) at the 22, 43, 86, and 129 GHz bands, as part of the
Interferometric Monitoring of Gamma-ray Bright AGNs (iMOGABA) KVN key science
program. Observations were conducted in 29 sessions from January 16, 2013 to
March 1, 2016, with the source being detected and imaged at all available
frequencies. In all epochs, the source was compact on the milliarcsecond (mas)
scale, yielding a compact VLBI core dominating the synchrotron emission on
these scales. Based on the multi-wavelength data between 15 GHz (Owens Valley
Radio Observatory) and 230 GHz (Submillimeter Array), we found that the source
shows multiple prominent enhancements of the flux density at the centimeter
(cm) and millimeter (mm) wavelengths, with mm enhancements leading cm
enhancements by -16$\pm$8 days. The turnover frequency was found to vary
between 21 to 69GHz during our observations. By assuming a synchrotron
self-absorption model for the relativistic jet emission in S5 0716+714, we
found the magnetic field strength in the mas emission region to be $\le$5 mG
during the observing period, yielding a weighted mean of 1.0$\pm$0.6 mG for
higher turnover frequencies (e.g., >45 GHz).