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Una galaxia de disco dinámicamente fría en el Universo temprano
F Rizzo1, S Vegetti2, D Powell2
1Max-Planck Institute for Astrophysics, Garching, Germany. frizzo@mpa-garching.mpg.de.
Nature
|August 14, 2020
Resumen
Se esperaba que las primeras galaxias fueran caóticas. Sin embargo, encontramos una galaxia de disco dinámicamente fría y giratoria con desplazamiento al rojo z = 4.2, desafiando los modelos anteriores de evolución de galaxias en el Universo joven.
Área de la Ciencia:
- La evolución cósmica
- Formación y dinámica de las galaxias
Sus antecedentes:
- Se predijo que las condiciones del Universo temprano (procesos astrofísicos extremos, fusiones, supernovas) formarían galaxias jóvenes dinámicamente calientes, caóticas e inestables.
- Los modelos actuales sugieren diferencias significativas entre las galaxias del Universo temprano y local debido a estas condiciones extremas.
Objetivo del estudio:
- Para investigar las propiedades dinámicas de las galaxias en el Universo temprano.
- Para determinar si las galaxias jóvenes podrían exhibir una rotación ordenada y ser dinámicamente frías, similares a las galaxias locales.
Principales métodos:
- Se utilizaron imágenes interferométricas de alta resolución espacial (aprox. 60 parsecs) para estudiar la galaxia SPT-S J041839-4751.9.
- Analizó la relación entre los movimientos rotacionales y aleatorios y derivó la curva de rotación de la galaxia.
- Aprovechó la lente gravitacional para observar la galaxia lejana.
Principales resultados:
- Descubrió un disco giratorio dinámicamente frío, altamente formador de estrellas en una galaxia con desplazamiento al rojo z = 4.2 (edad del Universo ~ 1.4 mil millones de años).
- Se midió una relación de movimientos rotacionales a aleatorios (9.7 ± 0.4), significativamente mayor que la prevista por los modelos para esta época.
- Derivado una forma de curva de rotación consistente con las galaxias espirales masivas cercanas.
Conclusiones:
- Al menos algunas galaxias en el Universo primitivo eran dinámicamente frías y ordenadas, parecidas a las galaxias espirales locales.
- Los hallazgos desafían la noción de que todas las galaxias jóvenes fueron fuertemente afectadas por procesos extremos del Universo temprano.
- Sugiere que las vías de evolución de las galaxias pueden conducir a discos dinámicamente fríos incluso en el universo naciente.
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