Low frequency radio monitoring of Cygnus X-1 and Cygnus X-3

Abstract

We present results of monitoring observations of the micro-quasars CygnusX-1 and Cygnus X-3 at 0.61 and 1.28 GHz. The observations were performed with Giant Meter-wave Radio Telescope, GMRT, between 2003 June and 2005 January. Variable, unresolved sources were found in both cases. Cyg X-1 was detected in about half of the observations, with a median flux density about 7 mJy at each frequency. The results show clearly that there is a break in the spectrum above 1.28 GHz. The variations in Cyg X-1 may be due to refractive interstellar scintillation. Cyg X-3 was detected in each observation, and varied by a factor of 4. For this source, models of the scintillation suggest a very long timescale (of the order of 40 yr at 1.28 GHz), and therefore we believe that the variations are intrinsic to the source.

arXiv comment8 pages, 7 figures, accpeted in A&A

References in corpus (10)

• A relativistic jet from Cygnus X-1 in the low/hard X-ray state
• A dark jet dominates the power output of the stellar black hole Cygnus X-1
• AU-Scale Synchrotron Jets and Superluminal Ejecta in GRS 1915+105
• Simultaneous X-ray and gamma-ray observations of Cyg X-1 in the hard state by Ginga and OSSE
• A One-sided, Highly Relativistic Jet from Cygnus X-3
• Orbital, precessional and flaring variability of Cygnus X-1
• Time-sequenced Multi-Radio-Frequency Observations of Cygnus X-3 in Flare
• The very flat radio - millimetre spectrum of Cygnus X-1
• Discovery of Correlated Behavior Between the HXR and the Radio Bands in Cygnus X-3
• Long term variability of Cygnus X-1, III. Radio-X-ray correlations

Cited by in corpus (8)

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• Spectral differences between the jets in `radio loud' and `radio quiet' hard state black hole binaries
• Gamma-ray observations of Cygnus X-1 above 100 MeV in the hard and soft states
• Lepto-hadronic model for the broadband emission of Cygnus X-1
• Spectral states of the X-ray binary IGR J17091--3624 observed by INTEGRAL and RXTE
• The variable radio counterpart of Swift J1858.6-0814