Space Telescope Science Institute
The super-massive black holes residing at the centers of many galaxies emit jets of relativistic plasma moving near the speed of light, a process which can deposit enormous amounts of energy into the host galaxy and inter-galactic medium. Yet the detailed physics behind these jets, including how they are launched and collimated, how long they remain relativistic, and their total energy content remain poorly understood. Using over 13 years of archival Hubble Space Telescope (HST) observations of the relativistic jet in the archetypal radio galaxy M87, we have produced astrometric speed measurements of the optically bright synchrotron emitting plasma components in the jet with unprecedented accuracy. Building on previous work showing the superluminal nature of the jet in the optical, we have found that the jet motion is incredibly complex, with both transverse motions and flux variations which can be seen by eye in the time series of deep exposures. These observations of M87 provide us with a unique dataset with which to refine theoretical models of the large-scale jet structure, potentially addressing open questions such as the jet collimation mechanism, bulk acceleration and deceleration in the jet, and the presence of a helical structure. I will also present very recent results using data from the HST archive on the optical counterjet and nuclear regions of M87 and discuss the larger implications of these detailed studies of one of the most nearby AGN jets.
Location: Physics Bldg., Room 401