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Una galaxia joven magnificada de unos 500 millones de años después del Big Bang
Wei Zheng1, Marc Postman, Adi Zitrin
1Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA. zheng@pha.jhu.edu
Nature
|September 22, 2012
Resumen
Las primeras galaxias, cruciales para la comprensión de la reionización cósmica, fueron detectadas utilizando lentes gravitacionales. Estas débiles y jóvenes galaxias parecen abundantes, potencialmente alimentando el medio intergaláctico.
Área de la Ciencia:
- Cosmología Cosmología.
- Evolución de la galaxia Evolución de la galaxia.
- El Universo Temprano Astrofísica Astrofísica
Sus antecedentes:
- La reionización del medio intergaláctico ocurrió alrededor del desplazamiento al rojo z ≈ 6-11.
- Las galaxias jóvenes, que forman estrellas menos de 500 millones de años después del Big Bang (z 10), son en gran parte inexploradas debido a los límites de sensibilidad de los telescopios actuales.
- Comprender estas primeras galaxias es clave para identificar las fuentes de radiación de reionización.
Objetivo del estudio:
- Para detectar y caracterizar galaxias débiles y de alto desplazamiento al rojo.
- Para investigar las propiedades de las galaxias en el Universo temprano.
- Identificar las fuentes potenciales responsables de la reionización del medio intergaláctico.
Principales métodos:
- Utilizó la lente gravitacional del cúmulo de galaxias MACS J1149+2223 para magnificar galaxias distantes.
- Se llevaron a cabo observaciones multibanda del cúmulo de galaxias.
- Analizó datos de galaxias magnificadas para determinar el corrimiento al rojo y el tiempo de formación.
Principales resultados:
- Se ha detectado una galaxia magnificada gravitacionalmente con desplazamiento al rojo z = 9,6 ± 0,2 (edad cósmica de 490 ± 15 millones de años).
- Se estima que la formación de galaxias ocurrió menos de 200 millones de años después del Big Bang (el desplazamiento al rojo de la formación 14).
- Abundancia observada de galaxias débiles en esta edad cósmica temprana.
Conclusiones:
- Las galaxias débiles parecen abundantes en el Universo temprano, lo que sugiere que pueden dominar la re-ionización temprana.
- La lente gravitacional es una herramienta poderosa para estudiar estas galaxias tempranas que de otro modo no serían detectables.
- Estos hallazgos proporcionan una visión crítica de las fuentes y mecanismos de la reionización cósmica.
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