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H I Emisión de 21 centímetros de un conjunto de galaxias a un desplazamiento al rojo promedio de uno
Aditya Chowdhury1, Nissim Kanekar2, Jayaram N Chengalur1
1National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune, India.
Nature
|October 15, 2020
Resumen
Los científicos midieron la masa de gas de hidrógeno atómico (H I) en las galaxias a un desplazamiento al rojo. Esta masa de gas es similar a la masa estelar y solo puede alimentar la formación de estrellas durante 1 a 2 mil millones de años, lo que sugiere que la insuficiente acreción de gas causó la disminución de la formación estelar cósmica.
Área de la Ciencia:
- Evolución cósmica de las galaxias
- Astrofísica y cosmología
- Contenido de gas galáctico
Sus antecedentes:
- La evolución de las galaxias implica la acumulación de gas, la conversión en estrellas y la formación de estrellas.
- La formación de estrellas cósmicas alcanzó su punto máximo en los desplazamientos al rojo 1-3 y disminuyó significativamente durante 10 mil millones de años.
- La medición de la masa de gas de hidrógeno atómico (HI) en galaxias distantes ha sido un desafío debido a la debilidad de la señal.
Objetivo del estudio:
- Para medir la masa media H I de las galaxias formadoras de estrellas a un desplazamiento al rojo.
- Para entender el papel del gas atómico en la formación de estrellas y la evolución de las galaxias.
- Para investigar las causas de la disminución de la densidad de la tasa de formación de estrellas cósmicas.
Principales métodos:
- Se utilizó el apilamiento de señales individuales de emisión H I de 21 centímetros de galaxias con desplazamiento al rojo uno.
- Las tasas de formación estelar promedio estimadas utilizando observaciones de continuo de radio de 1,4 gigahertz.
- Comparación de la masa de gas H I medida con los requerimientos de combustible para las tasas de formación estelar observadas.
Principales resultados:
- Se encontró que la masa media H I de las galaxias formadoras de estrellas en el corrimiento al rojo uno era similar a su masa estelar promedio.
- La masa de gas H I medida puede sostener las tasas de formación estelar observadas durante solo 1 a 2 mil millones de años sin que caiga gas fresco.
- Esto sugiere que la acreción de gas en las galaxias a desplazamientos al rojo menores de uno puede haber sido insuficiente.
Conclusiones:
- El reservorio de gas atómico limitado en las galaxias en un desplazamiento al rojo sugiere una acumulación de gas insuficiente.
- Esta insuficiente acreción de gas probablemente causó la disminución en la densidad de la tasa de formación de estrellas cósmicas a desplazamientos al rojo por debajo de uno.
- La comprensión de la caída de gas es crucial para una imagen completa de la evolución de la galaxia.
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