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Turbulencia de bajo número de Mach en el gas interestelar revelada por los gradientes de polarización de radio
B M Gaensler1, M Haverkorn, B Burkhart
1Sydney Institute for Astronomy, School of Physics, The University of Sydney, New South Wales 2006, Australia. bryan.gaensler@sydney.edu.au
Nature
|October 7, 2011
Resumen
Los investigadores obtuvieron imágenes de la turbulencia magnetizada en la Vía Láctea.
Área de la Ciencia:
- La astrofísica es la astrofísica.
- Física del plasma es la física del plasma.
- Estudios sobre el medio interestelar.
Sus antecedentes:
- El medio interestelar (ISM) es un entorno complejo, multifásico, magnetizado y turbulento.
- La caracterización de la turbulencia interestelar, incluido su número de Mach sónico, es crucial pero desafiante debido a las limitaciones de resolución.
- Se han observado estructuras polarizadas inusuales en la emisión de radio, pero su significado físico sigue sin estar claro.
Objetivo del estudio:
- Desarrollar un nuevo método para visualizar y cuantificar la turbulencia magnetizada en el gas ionizado difuso del ISM.
- Para determinar los parámetros fundamentales de la turbulencia interestelar, como el número de Mach sónico.
Principales métodos:
- Análisis del gradiente del vector de Stokes (Q, U) a partir de las observaciones de polarización de radio.
- Comparación de datos de observación con las simulaciones magnetohidrodinámicas (MHD) de la turbulencia interestelar.
- Desarrollo de herramientas estadísticas para el análisis de gradientes de polarización.
Principales resultados:
- El gradiente del vector de Stokes revela una estructura de red filamentaria, indicativa de una turbulencia magnetizada.
- La comparación con las simulaciones indica un bajo número de Mach sónico (M(s) 2) para la turbulencia en el medio ionizado caliente.
- El método muestra con éxito las discontinuidades en la densidad del gas y los campos magnéticos asociados con la turbulencia.
Conclusiones:
- El gradiente de la emisión de radio polarizada proporciona una nueva y poderosa herramienta para obtener imágenes de la turbulencia magnetizada en el ISM.
- La turbulencia interestelar en el medio ionizado caliente se caracteriza por un bajo número Mach sónico.
- Esta técnica permitirá la determinación precisa de los parámetros clave de la turbulencia (número de Mach, número de Reynolds, intensidad del campo magnético).
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