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A large nuclear accretion disk in the active galaxy NGC4261

O'Connell, Robert W.; Ferrarese, Laura; Ford, Holland C. +2 more

THE powerful emissions from the nuclei of active galaxies and quasars are thought to arise from the accretion of matter onto a massive black hole. Angular momentum will prevent matter from falling directly onto the central mass; instead, an 'accretion disk' should form, within which the gravitationally bound material will lose angular momentum and…

Detection of the hydroxyl radical in the Saturn magnetosphere

Shemansky, D. E.; Tripp, T. M.; Matheson, P. +2 more

THE magnetosphere in the vicinity of the orbits of Saturn's icy satellites consists of a low-density plasma, in which the electrons are an order of magnitude cooler than the accompanying heavy ions¹. Most models^2-12 neglect this fact, even though radiative cooling and diffusive loss rates are both too slow to account for the …

Internal structure and polarization of the optical jet of the quasar 3C273

Mackay, C. D.; Thomson, R. C.; Wright, A. E.

THE extragalactic radio source 3C273 was the first quasar to be identified¹, and remains one of the nearest and most luminous quasars known. In radio images^2-4, it appears as a bright, point-like nucleus from which emerges a single large jet; the jet is also apparent in optical images^5-8, but the relatively poor re…