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Abstract:

The accretion/ejection coupling in accreting black hole binaries has been described by empirical relations between the X-ray/radio and X-ray/optical-infrared luminosities. These correlations were initially supposed to be universal. However, recently many sources have been found to produce jets that, given certain accretion-powered luminosities, are fainter than expected from the correlations. This shows that black holes with similar accretion flows can produce a broad range of outflows in power Here we discuss whether typical parameters of the binary system, as well as the properties of the outburst, produce any effect on the energy output in the jet. We also define a jet-toy model in which the bulk Lorentz factor becomes larger than ∼ 1 above ∼ 0.1% of the Eddington luminosity. We finally compare the "radio quiet" black holes with the neutron stars. © International Astronomical Union 2011.

Abstract:

We report the discovery of multi-scale X-ray jets from the accreting neutron star X-ray binary, Circinus X-1. The bipolar outflows show wide opening angles and are spatially coincident with the radio jets seen in new highresolution radio images of the region. The morphology of the emission regions suggests that the jets from Circinus X-1 are running into a terminal shock with the interstellar medium, as is seen in powerful radio galaxies. This and other observations indicate that the jets have a wide opening angle, suggesting that the jets are either not very well collimated or precessing. We interpret the spectra from the shocks as cooled synchrotron emission and derive a cooling age of ∼1600 yr. This allows us to constrain the jet power to be 3×1035 erg s-1 ≲ Pjet ≲ 2×1037 erg s-1, making this one of a few microquasars with a direct measurement of its jet power and the only known microquasar that exhibits stationary large-scale X-ray emission. © 2010. The American Astronomical Society. All rights reserved.