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Ocho por ciento de fugas de fotones del continuo de Lyman de una galaxia enana compacta que forma estrellas
Y I Izotov1, I Orlitová2, D Schaerer3,4
1Main Astronomical Observatory, National Academy of Sciences of Ukraine, 27 Zabolotnoho street, Kyiv 03680, Ukraine.
Nature
|January 15, 2016
Resumen
Las galaxias de baja masa son la clave para reionizar el Universo. Las observaciones revelan que una galaxia cercana de formación estelar, J0925 + 1403, está filtrando radiación ionizante, lo que sugiere que estas galaxias pueden ionizar el medio intergaláctico.
Área de la Ciencia:
- La reionización cósmica
- Cosmología de observación
- Evolución de las galaxias
Sus antecedentes:
- La reionización del Universo después de la 'Edad Oscura' cósmica es una cuestión importante en la cosmología.
- Se supone que las galaxias de baja masa y formación estelar son las principales fuentes de radiación ionizante.
- La observación directa de galaxias de alto desplazamiento al rojo es un desafío, lo que requiere el estudio de proxies locales.
Objetivo del estudio:
- Para identificar las poblaciones de galaxias locales que pueden servir como proxies para las fuentes de reionización cósmica.
- Para investigar la fracción de escape de la radiación ionizante de las galaxias de baja masa de formación estelar cercanas.
Principales métodos:
- Observaciones en el ultravioleta lejano de la cercana galaxia de baja masa formadora de estrellas J0925+1403.
- Análisis de la fuga de radiación ionizante y de la fracción de escape.
Principales resultados:
- La galaxia J0925+1403 exhibe una fracción de escape significativa de radiación ionizante, aproximadamente del 8%.
- Esta fracción de escape es más alta que la observada anteriormente en galaxias similares de bajo desplazamiento al rojo (1-3%).
- Los fotones emitidos son suficientes para ionizar el material del medio intergaláctico significativamente más masivo que la propia galaxia.
Conclusiones:
- Las galaxias cercanas de baja masa formadoras de estrellas, como J0925 + 1403, son capaces de contribuir sustancialmente a la reionización del Universo.
- La alta fracción de escape observada apoya la hipótesis de que tales galaxias son las fuentes dominantes de radiación ionizante.
- El estudio adicional de estos análogos locales es crucial para comprender la época de la reionización.
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