Radio polarimetry as a probe of unresolved jets: The 2013 outburst of XTE J1908+094

XTE J1908+094 is an X-ray transient black hole candidate in the Galactic plane that was observed in outburst in 2002 and 2013. Here we present multifrequency radio and X-ray data, including radio polarimetry, spanning the entire period of the 2013 outburst. We find that the X-ray behaviour of XTE J1...

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Bibliographic Details
Main Authors: Curran, Peter, Miller-Jones, James, Rushton, A., Pawar, D., Anderson, G., Altamirano, D., Krimm, H., Broderick, J., Belloni, T., Fender, R., Körding, E., Maitra, D., Markoff, S., Migliari, S., Rumsey, C., Rupen, M., Russell, D., Russell, T., Sarazin, C., Sivakoff, C., Soria, R., Tetarenko, A., Titterington, D., Tudose, V.
Format: Journal Article
Published: Oxford University Press 2015
Online Access:http://hdl.handle.net/20.500.11937/36708
Description
Summary:XTE J1908+094 is an X-ray transient black hole candidate in the Galactic plane that was observed in outburst in 2002 and 2013. Here we present multifrequency radio and X-ray data, including radio polarimetry, spanning the entire period of the 2013 outburst. We find that the X-ray behaviour of XTE J1908+094 traces the standard black hole hardness–intensity path, evolving from a hard state, through a soft state, before returning to a hard state and quiescence. Its radio behaviour is typical of a compact jet that becomes quenched before discrete ejecta are launched during the late stages of X-ray softening. The radio and X-ray fluxes, as well as the light-curve morphologies, are consistent with those observed during the 2002 outburst of this source. The polarization angle during the rise of the outburst infers a jet orientation in agreement with resolved observations but also displays a gradual drift, which we associate with observed changes in the structure of the discrete ejecta. We also observe an unexpected 90° rotation of the polarization angle associated with a second component.