Il Nuovo Cimento C

, Volume 13, Issue 2, pp 453–462 | Cite as

Cygnus X-3: Six years of observations atE 0≥50 TeV from the Plateau Rosa array

  • C. Morello
  • L. Periale
  • P. Vallania
  • G. Navarra
Article

Summary

Cygnus X-3 has been observed from 1982 to 1987 at primary energyE 0≃1014 eV from the Plateau Rosa array. The absolute excess in the counting rate from the source region amounts to 0.15%, mostly concentrated in 1982 and 1986. The effect is observed in two classes of events although with small significance (2 and 1.4 s.d.). The 1986 data are consistent with observations of other arrays. The study of the 4.8 h time periodicity over a long observation time does not show any significant structure (2.5 s.d. excess at phase 0.2÷0.5). In 1982 and 1986 the light curves show respectively a wide excess between phases 0.60 and 0.85 and a 2.7 s.d. excess at phase 0.2÷0.25. The analysis of daily excesses from the source shows a good agreement with the expectations from pure statistical fluctuations, and no significant evidence of burst activity.

PACS 98.70.Qy

X-ray and γ-ray sources 

Riassunto

Cygnus X-3 è stato osservato dal 1982 al 1987 per mezzo dell'apparato sciami di Plateau Rosà alle energie primarieE 0≃1014 eV. Dalla regione della sorgente si misura un eccesso di conteggi dello 0.15%, essenzialmente concentrato nel 1982 e nel 1986. L'effetto è presente in due classi di eventi, seppure con bassa significatività (2 ed 1.4 d.s.). I dati del 1986 sono consistenti con le osservazioni di altri apparati. Le curve di luce, costruite utilizzando le effemeridi X (P≃4.8 h), su tempi lunghi non mostrano strutturu significative (2.5 s.d. a fase 0.2÷0.25). Nelle curve di luce degli anni 1982 e 1986 si osservano rispettivamente un eccesso distribuito tra fase 0.60 e 0.85 ed un picco (2.7 s.d.) alla fase 0.20÷0.25. L'analisi degli eccessi giornalieri mostra un buon accordo con quanto atteso da pure fluttuazioni poissoniane, e nessuna evidenza significativa di attività sporadica.

Резюме

Лебедь X-3 наблюдался с 1982 г. по 1987 г. при начальной энергииE 0≈1014 эВ на антенной решетке Плато Роза. Из области источника было зарегистрировано абсолютное превышение до 0.15% особенно в 1982 г. и в 1986 г. Этот эффект наблюдался в двух классах событий. Данные 1986 г. согласуются с данными, полученными на других антенных решетках. Исследование временной периодичности 4.8 ч в течение длительного времени наблюдения не обнаруживает кокой-либо структуры. В 1982 г и в 1986 г. наблюдались пики излучения при фазах (0.75÷0.80) и (0.2÷0.25), имеющие соответственно 3.17 и 1.98 стандартных отклонений. Анализ суточных превышений из источника обнаруживает хорошее согласие с предсказаниями статистических пуассоновских флуктуаций и не обнаруживает существенных подтверждений спорадической активности.

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Copyright information

© Società Italiana di Fisica 1990

Authors and Affiliations

  • C. Morello
    • 1
  • L. Periale
    • 1
  • P. Vallania
    • 1
  • G. Navarra
    • 1
    • 2
  1. 1.Istituto di Cosmo-geofisica del C.N.R.Torino
  2. 2.Istituto di Fisica Generale dell'UniversitàTorino

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