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Fuentes discretas como el origen de las emisiones de la cresta galáctica de rayos X
M Revnivtsev1, S Sazonov, E Churazov
1Excellence Cluster Universe, Technische Universität München, 85748, Garching, Germany. mikej@mpa-garching.mpg.de
Nature
|May 2, 2009
Resumen
La emisión de rayos X de la cresta galáctica, que anteriormente se pensaba que era gas caliente difuso, se resuelve en gran medida en fuentes discretas. Es probable que estas fuentes estén acumulando enanas blancas y estrellas activas, resolviendo un viejo rompecabezas astrofísico.
Área de la Ciencia:
- La astrofísica es la astrofísica.
- Astronomía de rayos X La astronomía de rayos X es una ciencia.
- La astronomía galáctica es la astronomía galáctica.
Sus antecedentes:
- Un brillo de rayos X sin resolver, conocido como la emisión de rayos X de la cresta galáctica, se ha observado durante 25 años.
- Esta emisión exhibe un espectro consistente con un plasma térmico caliente (aproximadamente 10^8 K) ópticamente delgado, con una línea de hierro prominente a 6,7 keV.
- El potencial gravitacional poco profundo del disco galáctico no puede confinar un medio interestelar tan caliente, lo que plantea un desafío significativo para la reposición de energía (10^43 erg s^-1).
Objetivo del estudio:
- Para investigar la naturaleza del brillo no resuelto de rayos X en el disco galáctico.
- Para determinar si la emisión de rayos X observada se origina en plasma difuso o fuentes discretas.
- Identificar los tipos de objetos celestes responsables de la emisión de rayos X de la cresta galáctica.
Principales métodos:
- Análisis de datos de rayos X a energías de aproximadamente 6-7 keV.
- Comparación de las distribuciones de brillo superficial de rayos X con los datos del infrarrojo cercano que rastrean la distribución estelar.
- Observaciones de rayos X de alta resolución para resolver la emisión difusa en fuentes puntuales.
Principales resultados:
- Más del 80% de la emisión de rayos X aparentemente difusa a 6-7 keV se resuelve en fuentes discretas.
- La distribución de estas fuentes discretas se correlaciona con la distribución estelar galáctica.
- Las fuentes identificadas son probablemente enanas blancas en acreción y estrellas coronalmente activas.
Conclusiones:
- La emisión de rayos X de la cresta galáctica no es principalmente gas caliente difuso, sino más bien la emisión agregada de numerosas fuentes débiles y discretas.
- Las enanas blancas en acrecentamiento y las estrellas activas son los probables contribuyentes a esta emisión.
- Este hallazgo resuelve el problema de larga data de la reposición de energía para el supuesto medio interestelar caliente en el disco galáctico.
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