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El crecimiento de la galaxia en un halo masivo en los primeros mil millones de años de la historia cósmica
D P Marrone1, J S Spilker1, C C Hayward2,3
1Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, Arizona 85721, USA.
Nature
|December 7, 2017
Resumen
Los astrónomos descubrieron un par de galaxias masivas que se fusionan con un desplazamiento al rojo de 6.9, menos de 800 millones de años después del Big Bang. Este descubrimiento revela estructuras cósmicas raras y tempranas y proporciona información sobre la formación de galaxias.
Área de la Ciencia:
- Cosmología
- Formación y evolución de las galaxias
- La astrofísica del Universo temprano
Sus antecedentes:
- Los modelos de formación de estructuras cósmicas predicen precursores tempranos de galaxias en regiones de alta densidad.
- La observación de estas estructuras masivas tempranas es un desafío debido a la sensibilidad de detección y los requisitos de ancho de sondeo.
- Se han detectado pocos objetos de este tipo, lo que pone de relieve la rareza de los primeros precursores de galaxias masivas.
Objetivo del estudio:
- Para informar sobre el descubrimiento y la caracterización de un raro objeto luminoso en el infrarrojo lejano con alto corrimiento al rojo.
- Para investigar las propiedades de las galaxias de formación estelar extremadamente masivas en el Universo temprano.
- Comprender los mecanismos de formación y las influencias ambientales en las primeras galaxias masivas.
Principales métodos:
- Utilizó encuestas de amplio campo para la detección inicial de objetos distantes y luminosos.
- Imágenes de alta resolución para resolver la estructura del objeto detectado.
- Los datos espectrales analizados para determinar el corrimiento al rojo, las tasas de formación de estrellas y el contenido de gas / polvo.
Principales resultados:
- Descubrió un par de galaxias formadoras de estrellas extremadamente masivas con desplazamiento al rojo de 6.9 (aprox. 800 millones de años después del Big Bang).
- La galaxia más grande exhibe una tasa de formación estelar de 2.900 masas solares por año, con 270 mil millones de masas solares de gas y 2.5 mil millones de masas solares de polvo.
- La galaxia compañera tiene 35 mil millones de masas solares de estrellas y una tasa de formación estelar de 540 masas solares / año, con mucho menos gas y polvo.
Conclusiones:
- Las galaxias observadas sugieren la presencia de un halo de materia oscura que excede las 100 mil millones de masas solares, entre las más raras esperadas en esta época.
- La rápida formación de estrellas en la galaxia más grande es probablemente provocada por su compañera de fusión.
- Estos hallazgos ofrecen información crucial sobre el montaje de las estructuras cósmicas más masivas en el Universo primitivo.
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