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C. Ly (UCLA), R. C. Walker (NRAO/Socorro), W. Junor (LANL)
New 43 GHz VLBI observations of M87 along with previous observations at 43 GHz and one observation at 22 GHz are presented. These data allow us to image the base of the jet where many questions regarding the formation of radio jets are left unanswered. These observations occurred in 1999, 2000, 2001, 2002 and 2004. The counter-jet for M87 has been detected from a 22 GHz observation and three epochs at 43 GHz. Moreover, at 43 GHz the edge-brightened structure is present at each epoch and a wide opening angle at the base is confirmed from an averaged image of all the epochs.
Proper motion measurements at 43 GHz reveal that lower limits on the pattern speed of the jet are 0.25 to 0.40c and 0.17c for the counter-jet. Therefore, yearly-sampled epochs cannot provide accurate proper motion measurements. These results lead us to pursue more observations to make a proper movie of the jet base of M87 at 43 GHz with the VLBA. This project was conducted through the NRAO Summer Student program with partial support from the National Science Foundation.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.