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Una distancia a la galaxia NGC4258 de las observaciones de las estrellas variables Cefeidas
E Maoz1, J A Newman, L Ferrarese
1NASA Ames Research Center, MS 245-3, Moffett Field, California 94035-1000, USA. maoz@ism.arc.nasa.gov
Nature
|July 25, 2006
Resumen
Las estrellas variables cefeidas son cruciales para medir las distancias cósmicas. Las nuevas observaciones de NGC4258 muestran una discrepancia entre las distancias de las cefeidas y las mediciones basadas en máseres, lo que podría afectar a la constante de Hubble y al universo.
Área de la Ciencia:
- La astronomía y la astrofísica.
- Cosmología Cosmología.
Sus antecedentes:
- Las estrellas variables cefeidas sirven como velas estándar para las mediciones de distancias extragalácticas.
- Las distancias exactas son esenciales para determinar la constante de Hubble y la edad del universo.
Objetivo del estudio:
- Para investigar discrepancias en las mediciones de distancia a la galaxia NGC4258.8.
- Evaluar el impacto de los posibles errores sistemáticos en los cálculos de distancia a las estrellas variables de las Cefeidas.
Principales métodos:
- Observaciones de las estrellas variables Cefeidas en NGC4258.8.
- Comparación con una distancia geométrica independiente derivada de los movimientos propios del máser de agua.
Principales resultados:
- La distancia basada en cefeidas a NGC4258 es de 8,1 ± 0,4 Mpc.
- La distancia geométrica independiente de las masas de agua es de 7.2 ± 0.5 Mpc.
- La diferencia entre las dos mediciones es de 1.3 sigma.
Conclusiones:
- Una escala de distancia Cefeida revisada, si adopta la distancia basada en el máser, aumentaría la constante de Hubble en 12 ± 9%.
- Esta revisión también disminuiría la edad de expansión calculada del universo en el mismo porcentaje.
- Las posibles incertidumbres sistemáticas en las distancias de las Cefeidas requieren una investigación adicional.
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