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Autori: V. Tudose, R.P. Fender, C.R. Kaiser, A.K. Tzioumis, M. van der Klis, R.E. Spencer
Editorial: Monthly Notices of the Royal Astronomical Society, 372, p.417, 2006.
We present multi-epoch observations of the radio nebula around the neutron star X-ray binary Circinus X-1 made at 1.4 and 2.5 GHz with the Australia Telescope Compact Array between 2000 October and 2004 September. The nebula can be seen as a result of the interaction between the jet from the system and the interstellar medium and it is likely that we are actually looking toward the central X-ray binary system through the jet-powered radio lobe. The study of the nebula thus offers a unique opportunity to estimate for the first time using calorimetry the energetics of a jet from an object clearly identified as a neutron star. An extensive discussion on the energetics of the complex is presented: a first approach is based on the minimum energy estimation, while a second one employs a self-similar model of the interaction between the jets and the surrounding medium. The results suggest an age for the nebula of <=10^5 yr and a corresponding time-averaged jet power >=10^35 erg s^-1. During periodic flaring episodes, the instantaneous jet power may reach values of similar magnitude to the X-ray luminosity.
Cuvinte cheie: accretion, accretion discs: radiation mechanisms: non-thermal: stars: individual: Circinus X-1: ISM: jets and outflows: radio continuum: stars: X-rays: stars