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J. M. Attridge (MIT Haystack Observatory), D. C. Homan, J. F. C. Wardle (Brandeis University), T. P. Krichbaum (MPIfR)
VLBI observations provide morphological and evolutionary information about AGN. In particular, knowledge about the structure and orientation of magnetic fields in the radio jets of these sources may be obtained through VLBI polarimetry. At centimeter wavelengths, VLBI observations have shown that polarized relativistic shocks in radio jets appear as superluminal knots.
High-resolution VLBI imaging of the cores of AGN is restricted by physical conditions of the disks surrounding the central engines. 3mm- VLBI polarization observations should probe magnetic field order by reducing the effects of Faraday rotation (\propto\lambda2) and depolarization.
Here we present 3mm-CMVA images of the quasars 3C279 and 3C273. These images are the first total intensity and linear polarization images made of any source at 3mm. 3mm-VLBI polarimetry harbors a number of calibration challenges, so the images presented here are calibration limited.
In this first epoch (1997.3), 3C279 displays total fractional linear polarization of 7.5%, most of which is located in a component west of the core. 3C273 appears unpolarized at this epoch. New short baseline data which is more sensitive to intermediate scale structure will be presented and discussed in the context of the initial 3mm epoch and recent 7mm images.
The CMVA research at Haystack is sponsored by the National Science Foundation.