We present analysis results of Korean VLBI Network (KVN) four-band data for the highly variable blazar 3C 279. We measured the 22, 43, 86, and 129 GHz flux densities and spectral indices of the source using contemporaneous data taken over 5.6 years. We used the discrete correlation function to investigate correlations between the radio emission properties and those measured in the optical (2 × 1014 – 1.5 × 1015 Hz), X-ray (0.3–10 keV), and gamma-ray (0.1–300 GeV) bands. We found a significant correlation between the radio spectral index and gamma-ray flux without a time delay and interpreted the correlation using an extended jet scenario for blazar emission.

1. INTRODUCTION
2. DATA REDUCTION
3. DATA ANALYSIS
3.1 Measurements of radio spectral index
3.2 Discrete Correlation Function (DCF) Analysis
4. Discussion and Conclusions
ACKNOWLEDGMENTS
REFERENCES

• Sungmin Yoo(Department of Astronomy and Space Sciences, Chungbuk National University)
• Hongjun An(Department of Astronomy and Space Sciences, Chungbuk National University) Corresponding author
• Sang-Sung Lee(Korea Astronomy and Space Science Institute, Astronomy and Space Science, University of Science and Technology)
• Sang-Hyun Kim(Korea Astronomy and Space Science Institute, Astronomy and Space Science, University of Science and Technology)