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Un bajo nivel de luz de fondo extragaláctica revelado por los rayos gamma de los blazars
F Aharonian1, A G Akhperjanian, A R Bazer-Bachi
1Max-Planck-Institut für Kernphysik, PO Box 103980, D 69029 Heidelberg, Germany.
Nature
|April 21, 2006
Resumen
Los investigadores estudiaron la difusa luz de fondo extragaláctica utilizando espectros de rayos gamma de los blazares. Los hallazgos sugieren que la luz estelar de las galaxias domina esta luz, excluyendo una contribución significativa de los primeros tiempos.
Área de la Ciencia:
- La astronomía y la astrofísica.
- Radiación cósmica de fondo de microondas de fondo cósmico.
Sus antecedentes:
- La luz de fondo extragaláctica difusa (DEBL) es la luz estelar integrada de las galaxias a lo largo de la historia cósmica.
- El DEBL puede incluir contribuciones de las primeras estrellas del Universo, anteriores a la formación de galaxias.
- La medición directa del DEBL es un desafío debido a la luz de primer plano, como la luz zodiacal.
Objetivo del estudio:
- Para restringir la composición de la difusa luz de fondo extragaláctica.
- Investigar la contribución de las primeras estrellas al DEBL.
- Para evaluar la transparencia del espacio intergaláctico a los rayos gamma.
Principales métodos:
- El análisis de los espectros de rayos gamma de blazars distantes (H 2356-309 y 1ES 1101-232).
- Estudiar las características de absorción en los espectros de rayos gamma causados por las interacciones de fotones con el DEBL.
- Utilizando espectros de blazar para establecer límites superiores en la intensidad DEBL.
Principales resultados:
- Se detectó la emisión de rayos gamma de blazars en desplazamientos al rojo z = 0.165 y z = 0.186.
- Se observaron espectros de rayos gamma inesperadamente duros de estos blazars.
- Se estableció un límite superior para el DEBL óptico/infrarrojo cercano cerca de la luz integrada de las galaxias resueltas.
Conclusiones:
- La difusa luz de fondo extragaláctica está fuertemente dominada por la luz estelar directa de las galaxias.
- Se excluye una contribución significativa de las primeras estrellas al DEBL.
- El espacio intergaláctico demuestra una mayor transparencia a los rayos gamma de lo que se suponía anteriormente.
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