Episodic jets from black holes and protostars
Article Abstract:
Active galactic nuclei, binary stellar systems with a black hole or a white dwarf, and stars in the process of formation are observed to produce highly collimated, energetic and episodic jets. The production of these jets is examined using time-dependent magnetohydrodynamical simulations. The findings indicate that outflows can be accelerated and collimated into jets by magnetic fields connected in the accretion disk. Episodic knots within the jet develop for particular magnetic field formations.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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How black holes stay black: There is probably a massive black hole at the centre of our Galaxy, and perhaps at the centre of most galaxies
Article Abstract:
There is evidence that large black holes exist in the centres of many normal galaxies, but cause much less radiation than expected. The massive black hole accretion model has been a standard explanation for the energy output of quasars. Astronomers have tested the black-hole model and it is indicated that the central dark mass in the galaxy NGC4258 and the Galatic Centre is a black hole. Black holes are believed to be so black because of their inefficient conversion of their food into radiation.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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Brilliance without black holes
Article Abstract:
Star formation rather than activity surrounding black holes may generate the active galactic nuclei (AGN), the extremely bright cores observed in 10% of galaxies. Roberto Terlevich and colleagues argue that the spectral features of AGNs can be explained more concisely in terms of well-established stellar processes than by invoking the strange astrophysical effects produced by black holes.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1992
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