Eileen MeyerSpace Telescope Science InstituteHEAD Meeting | 8 April 2013Proper Motion of the Optical Synchrotron Jet in M87

Bill Sparks, John Biretta,Tony Sohn, Jay Anderson,Roland Van der Marel, Marco Chiaberge,Colin Norman (JHU)1Why Study M87?

Jetted AGN Many Fundamental Open QuestionsNearby: 16.4 0.5 Mpc = 78 pc/arcsec (Bird 2010)Extensively studied from low-freq. radio to TeV(polarimetry, imaging, VLBI proper motions, etc.)

What is the Matter Content?What is the exact collimation mechanism?Jet Structure on small and large scales? (Spine-sheath?)Knots: Ballistic movements of dense plasma, standing or oblique shocks?

HST-1 D E F I A/B C2Proper Motions Study with HST

Using all available HST archival imaging: WFPC2, ACS/HRC, ACS/WFCCovering nearly 13 years (1995 2008)Well-sampled: nearly 400 total raw exposures3

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SummaryUnprecedented Accuracy in Optical Proper Motions (0.01c)New Scales: knots F,I,A,C (> 6 arcsec) & detailed velocity fieldMotion of HST-1 Connected with FlaringClear signs of Stationary ShocksAs well as Non-radial motions perp. to jet. ----> see more at www.stsci.edu/~meyer/M87.html