A possible hydrodynamical equivalence for astrophysical jets

 

S. Mendoza, X. Hernández, and W. H. Lee

 

Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 70-264, 04510 México, D. F., México (xavier@astroscu.unam.mx, wlee@astroscu.unam.mx, sergio@astroscu.unam.mx).

 

Received 2004 August 11
Accepted 2005 June 6

 

RESUMEN

La idea de un modelo unificado para cuasares y μ-cuasares ha sido considerada por bastante tiempo, a pesar de los distintos ambientes y condiciones físicas sobre los cuales ambas clases de objetos residen. En este trabajo mostramos la existencia de una ley de escalamiento simple, que relaciona el tamaño máximo de un chorro con las propiedades físicas del gas del entorno sobre el cual se expande. Este resultado es aparentemente válido para todo tipo de chorros hidrodinámicos y puede considerársele como un modelo general de unificación. La velocidad de expansión del chorro y las propiedades físicas del gas alrededor de éste se combinan de tal manera que ponen un límite máximo al tamaño que los chorros de distintas clases pueden tener.

 

ABSTRACT

The idea of a unified model for quasars and μ-quasars has been considered for a long time, despite the different environments and physical conditions where both classes of objects reside. Here we show the existence of a simple scaling law, relating the maximum size of a jet to the properties of the gas medium into which it expands. This appears to be valid for all types of hydrodynamical jets, and can be thought of as a broad unified model. The expansion velocity of the jet and the physical properties of the surrounding gas combine in such a way that a limit to the maximum extent of jets at different scales can be obtained.

Key Words: Galaxies: jets — Gamma rays: Bursts — Hydrodinamics — ISM: Jets and outflows — Quasars: General.

 

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ACKNOWLEDGMENTS

We would like to thank T. Arshakian, J. Cantó, M. Choudhury, and E. Ramírez-Ruiz for many fruitful discussions on μ-quasars, γ-ray bursts and jets in general while preparing this paper. We are very thankful to the anonymous referee for his comments, which provided a better physical understanding of the problem. S. Mendoza gratefully acknowledges financial support from CONACyT (41443) and DGAPA-UNAM (IN119203).

 

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