The nucleus and jet of Virgo~A at $10^{-2}$ parsec resolution.
Session 109 -- Extragalactic Radio Sources, Jets
Display presentation, Thursday, 12, 1995, 9:20am - 6:30pm

## [109.13] The nucleus and jet of Virgo~A at $10^{-2}$ parsec resolution.

W.\ Junor (UNM), J.A.\ Biretta (STScI)

Global VLBI observations at $\lambda1.3\,cm$ have been made of the bright, nearby, radio galaxy Virgo A (3C274). The host galaxy, M87, contains the prototypical extragalactic jet which has been well-studied at all wavelengths from radio to X-ray.

We show images with linear resolutions of $\sim0.01\,pc$ at two epochs separated by 5 months. These are the highest linear resolution images achieved so far on an active galactic nucleus. This resolution corresponds to $\sim10^{2}$ Schwarzchild radii for the supermassive black hole ($\sim3\times10^{9} \,M_{\odot}$) suggested by recent {\sl HST} observations of this galaxy.

Our new VLBI observations reveal a compact core and well-collimated jet, which are remarkably similar to those seen on much larger spatial scales. The core is mildly variable ($\sim30\%$ in $\sim$5 months). The jet is well collimated on these scales (opening angle $\sim 18 ^{\circ}$), and indicates that most of the initial jet collimation occurs well within $\sim$1 pc of the engine. No proper motion above the detection limit of $0.03\,c$ is seen in the jet. The implications of this measurement in the context of other proper motion measurements farther out in the jet are examined. (Also see Biretta \& Junor.)