[Previous] | [Session 75] | [Next]
R.T. Zavala (New Mexico State University and NRAO), G.B. Taylor (NRAO)
Using the VLBA we have obtained high resolution (submilliarcsecond) Faraday Rotation Measure (RM) images of the quasars 3C273 and 3C279. Our 2000 January 27 observation was made by combining observations at 8, 12, 15, 22, and 43 GHz. We see variations in the RM of these quasars on short spatial (<10 pc) and temporal (3 year) scales. The most striking variation on temporal and spatial scales occurs in 3C273. In our low resolution 8-15 GHz RM maps we see that this quasar's central region has changed from a uniform ~ -2000 rad/{\rm m2} 3 years ago to a more complex structure which ranges in {\mid{\rm RM}\mid} by ~ 2500 rad/{\rm m2} over little more than 10 pc. Our high resolution RM map resolves this structure into individual components which change by 103 rad/{\rm m2} on the scale of a few parsecs. The quasar 3C279 displays lower RM values, but also exhibits a temporal variability over a three year time span. We suggest that the variations in RM in both quasars are due to the narrow-line region, which acts as an irregular Faraday screen, sampled at various lines-of-sight by the moving jet components.
The author(s) of this abstract have provided an email address for comments about the abstract: rzavala@nmsu.edu