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Pulsar de milisegundos PSR 1937+21: un reloj muy estable.
Science (New York, N.Y.)
|November 6, 1987
Resumen
PSR 1937+21, un púlsar, demuestra una notable estabilidad de frecuencia, rivalizando con los relojes atómicos. Esta investigación proporciona un nuevo límite superior para la densidad de energía de la radiación gravitacional cósmica.
Área de la Ciencia:
- La astronomía es la astronomía.
- La astrofísica es la astrofísica.
- La astronomía de los púlsares es la astronomía de los púlsares.
Sus antecedentes:
- Los púlsares, como el PSR 1937+21, exhiben una rotación estable y pulsos de radio agudos.
- Estas características permiten que los púlsares funcionen como relojes cósmicos de alta precisión.
- Los relojes atómicos representan el estándar actual para la estabilidad de frecuencia a largo plazo.
Objetivo del estudio:
- Para evaluar la estabilidad de frecuencia a largo plazo del púlsar PSR 1937+21.
- Para comparar la estabilidad del púlsar con los relojes atómicos de última generación.
- Para establecer un límite superior para la densidad de energía de un fondo cósmico de radiación gravitacional.
Principales métodos:
- Utilizando el radiotelescopio de Arecibo para mediciones precisas de los tiempos de llegada de los pulsos.
- Empleando técnicas avanzadas de medición para lograr incertidumbres de aproximadamente 300 nanosegundos en relación con el tiempo atómico.
- Realización de mediciones quincenales desde noviembre de 1982 para analizar las tendencias de estabilidad a largo plazo.
Principales resultados:
- PSR 1937+21 exhibe una estabilidad de frecuencia fraccionaria de al menos 6 x 10 ((-14) para tiempos de promedio superiores a 4 meses.
- La precisión de la medición parece limitada por la estabilidad de los relojes atómicos de referencia en intervalos prolongados.
- Se determinó un límite superior firme de 7 x 10(-36) g/cm3 para la densidad de energía de la radiación gravitacional a 0,23 ciclos por año.
Conclusiones:
- El púlsar PSR 1937+21 sirve como un reloj altamente estable, superando potencialmente los relojes atómicos.
- El estudio proporciona restricciones cruciales sobre la densidad de la radiación gravitacional cósmica.
- El límite derivado para la radiación gravitacional es aproximadamente 4 x 10 ((-7) de la densidad requerida para cerrar el universo.
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