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Un rastro de galaxias libres de materia oscura de una colisión de bala y enano
Pieter van Dokkum1, Zili Shen2, Michael A Keim2
1Department of Astronomy, Yale University, New Haven, CT, USA. pieter.vandokkum@yale.edu.
Nature
|May 18, 2022
Resumen
Las galaxias ultra difusas DF2 y DF4 probablemente se formaron a partir de una sola colisión cósmica hace ocho mil millones de años. Este evento creó un rastro de galaxias libres de materia oscura, ofreciendo información sobre la formación de galaxias.
Área de la Ciencia:
- La astronomía galáctica
- Evolución de las galaxias
- Cosmología
Sus antecedentes:
- Las galaxias ultra difusas DF2 y DF4 exhiben rasgos peculiares: grandes tamaños, abundantes cúmulos globulares superluminosos y una materia oscura mínima.
- Las teorías anteriores proponían colisiones de alta velocidad de galaxias ricas en gas, similares al cúmulo de balas, como su mecanismo de formación.
Objetivo del estudio:
- Para investigar la hipótesis de formación de las galaxias ultra difusas DF2 y DF4.
- Para determinar si estas galaxias se originaron en un solo evento de colisión cósmica.
Principales métodos:
- Análisis de las distancias de la línea de visión y las velocidades radiales de DF2 y DF4.
- Examen de la distribución espacial y las características de los objetos de baja luminosidad asociados.
Principales resultados:
- Las distancias y velocidades observadas de DF2 y DF4 apoyan su formación conjunta hace aproximadamente ocho mil millones de años de una sola colisión "bala-enano".
- DF2 y DF4 son parte de una estructura lineal de 7-11 objetos, lo que sugiere un rastro de galaxias libres de materia oscura de más de 2 megaparsecs de largo.
- Identificación tentativa de los restos dominados por la materia oscura de las galaxias progenitoras en los bordes del rastro.
Conclusiones:
- Un solo evento de colisión "bala-enano" es una explicación plausible para la formación de DF2, DF4 y las galaxias asociadas.
- Este evento probablemente produjo un rastro único de galaxias libres de materia oscura, desafiando los modelos convencionales de formación de galaxias.
- Los hallazgos proporcionan una nueva perspectiva sobre la formación de galaxias a través de colisiones cósmicas de alta energía.
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