科研之友
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摘要
I examine a mechanism by which two fast narrow jets launched by a newly formed neutron star (NS), or a black hole (BH), at the centre of a core-collapse supernova (CCSN), form two slow massive wide (SMW) jets. Such SMW jets are assumed as initial conditions in some numerical simulations that demonstrate that SMW jets can expel the rest of the collapsing star. The original fast narrow jets must deposit their energy inside the star via shock waves and form two hot bubbles that accelerate a much larger mass to form SMW jets. To prevent the jets from penetrating through the still infalling gas and escape instead of forming the hot bubbles, the jets should encounter fresh infalling gas. This condition is met if the jet's axis changes its direction. The exact condition is derived. In addition, to maintain a small neutrino cooling the fast narrow jets must be shocked at a distance r greater than or similar to 10(3) km from the core, such that most of the post-shock energy is in radiation, and temperature is not too high. The scenario proposed here was shown to be able to suppress star formation in newly formed galaxies, and in forming SMW jets in cooling flow clusters of galaxies and in planetary nebulae. Namely, I suggest that NSs (or BHs) at the centre of CCSNe shut off their own growth and expel the rest of the mass available for accretion using the same mechanism by which supermassive BHs shut off their own growth, as well as that of their host bulge, in young galaxies.
- 出版日期2010-2-1
