A magnetic switch that determines the speed of astrophysical jets.
The mechanism by which astrophysical jets form is an important factor in understanding the nature and evolution of phenomena such as active galactic nuclei and quasars, Galactic superluminal X-ray sources and young stellar objects. Of the many schemes proposed for jet production, only the magnetized...
| Main Authors: | , , , , |
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| Format: | |
| Language: | English |
| Published: |
1997
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| Online Access: | http://ezproxy.villanova.edu/login?url=https://digital.library.villanova.edu/Item/vudl:176408 |
| Summary: | The mechanism by which astrophysical jets form is an important
factor in understanding the nature and evolution of phenomena
such as active galactic nuclei and quasars, Galactic superluminal
X-ray sources and young stellar objects. Of the many schemes
proposed for jet production, only the magnetized accretion disk
model of Blandford and Payne1 seems to be applicable to all of
these systems, and also offers the potential for generating the
highly relativistic flows observed in some quasars2. But the source
of variation in jet morphology observed for different sources
remains unclear. Here we report time-dependent numerical
simulations of jet formation which show that the character and
speed of the jets produced depend dramatically on whether
magnetic forces dominate over gravity in the accretion disk
corona. This 'magnetic switch' is not predicted by steady-state,
self-similar disk models, or by relativistic wind theory (which
generally ignores the gravitational field). The effect provides a
natural explanation for the existence of two known classes of
extragalactic radio source and for the variation of their properties
with radio luminosity. It also provides insight into protostellar
and galactic microquasar systems. |
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