اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدA decade of radio imaging the relativistic outflow in the peculiar X-ray binary Circinus X-1
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We present observations of the neutron star X-ray binary and relativistic jet source Circinus X-1 made at 4.8 and 8.6 GHz with the Australia Telescope Compact Array during a time interval of almost 10 years. The system shows significant variations in the morphology and brightness of the radio features on all timescales from days to years. Using the time delay between the successive brightening of the different components of the radio emission we were able to provide further evidence for the relativistic nature of the arcsec scale outflow, with an apparent velocity beta_app >= 12. No compelling evidence for an evolution of the orientation of the jet axis was found. We also place an upper limit on the proper motion of the system which is consistent with previous optical studies. Besides the previously reported radio flares close to the orbital phase 0.0 (interpreted as enhanced accretion at periastron passage), we also identified outbursts with similar properties near the orbital phase 0.5. The global spectral index revealed a preferentially steep spectrum over the entire period of monitoring with a mean value and standard deviation alpha=-0.9 +/- 0.6 (F_nu ~ nu^{alpha}), which became significantly flatter during the outbursts. Polarization was detected in one third of the epochs and in one case Faraday rotation close to the core of the system was measured.
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We present the results of simultaneous X-ray and radio observations of the peculiar Z-type neutron star X-ray binary Cir X-1, observed with the Rossi X-ray timing explorer satellite and the Australia Telescope Compact Array in 2000 October and 2002 D
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We present the results of the analysis of two Chandra observations of Circinus X-1 performed in 2007, for a total exposure time of ~50 ks. The source was observed with the High Resolution Camera during a long X-ray low-flux state of the source. Cir X
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We present an analysis of long term X-ray monitoring observations of Circinus X-1 (Cir X-1) made with four different instruments: Vela 5B, Ariel V ASM, Ginga ASM, and RXTE ASM, over the course of more than 30 years. We use Lomb-Scargle periodograms t
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