VLBI Images of 3C279 During the Multiwavelength Campaign in 1992/1993
Session 107 -- BL Lacs and Blazars
Display presentation, Saturday, January 15, 9:30-6:45, Salons I/II Room (Crystal Gateway)

## [107.09] VLBI Images of 3C279 During the Multiwavelength Campaign in 1992/1993

A.E. Wehrle (IPAC/Caltech/JPL), S. C. Unwin (Caltech), A.C. Zook (Pomona College), G. Madejski (USRA, GSFC), L. Maraschi (Milan), C. M. Urry (STScI)

We present Global VLBI images of the quasar 3C279. In the core and shocks in the jet, inverse Compton scattering may produce x-ray and $\gamma$-ray photons detected by ROSAT and CGRO. The observations were made at 5 and 22 GHz during 1992 and 1993 using 12-16 antennas, including seven VLBA antennas. The synthesized beam (FWHM) was $\sim 1$ milliarcsecond ($\sim 3$ pc) at 5 GHz and $\sim 0.25$ milliarcseconds at 22 GHz.

The 5 GHz image of June 1992 shows a core-jet structure. A bright blob in the jet was brighter than the core at this epoch. The jet appeared clumpy within $\sim 6$ milliarcseconds of the core, then it became diffuse for another $\sim 10$ milliarcseconds until it faded below the noise level.

The 22 GHz image of November 1992 shows a slightly resolved core and a clumpy jet. A new component appeared to be separating from the core. The 22 GHz core-jet structure had a total extent of about 2 milliarcseconds, with the jet terminating abruptly.

Possible relationships between changes in the core-jet structures and the x-ray and $\gamma$-ray emission will be discussed.