VLBA observations of 0716+714

The BL Lac object 0716+714 has a very compact radio structure with a dominant core and a weak jet at a position angle ∼ 15 ◦ (e.g., Bach et al., 2005). Because the optical spectrum is featureless, the exact redshift is unknown. However, a recent detection of a host galaxy give value of z ∼ 0.3 (Nilsson et al., 2008). 0716+714 exhibits high variability in intensity and polarization from timescales of hours to years. Detection of correlated intraday variability (IDV) in different wavelengths (Wagner et al., 1996) and rapid variability in the mm domain (Agudo et al., 2006) suggest that the flux variations are intrinsic. High Doppler boosting is needed to explain the observed brightness temperature in the framework of the standard synchrotron source model with a power-law electron energy distribution. While results of the long term radio monitoring in Metsähovi Radio Observatory (Hovatta et al., 2008) suggest moderate Doppler factor of 10, previous VLBI studies (Jorstad et al., 2001; Bach et al., 2005) propose a Doppler factor of up to 30. We carried out 5 multifrequency VLBA observations in 2004, the epochs were separated by approximately a month. With these observations we were able to study jet kinematics wit