Gamma-ray astronomy

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The Continuous Jets of Cygnus X-1

Chapter in Microquasars, Springer Nature (2001) 255-258

Authors:

R Spencer, C De La Force, A Stirling, M Garrett, R Fender, R Ogley
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The Disc — Jet Connection in GRS 1915+105

Chapter in Microquasars, Springer Nature (2001) 291-292

Authors:

M Klein-Wolt, RP Fender, GG Pooley, T Belloni, S Migliari, EH Morgan, M Van Der Klis
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The Stellar Populations of Nearby Radiogalaxies

Chapter in Starburst Galaxies: Near and Far, Springer Nature 88 (2001) 157-162

Authors:

Itziar Aretxaga, Elena Terlevich, Roberto J Terlevich, Garret Cotter, Angeles I Díaz
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VLBA Observations of the Superluminal Radio Jet from Cygnus X-1 in the Low/Hard X-Ray State

Chapter in Microquasars, Springer Nature (2001) 121-122

Authors:

Chris De La Force, Ralph Spencer, A Stirling, M Garrett, R Fender
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Coupling of the X-ray and radio emission in the black hole candidate and compact jet source GX 339-4

Astronomy and Astrophysics 359:1 (2000) 251-268

Authors:

S Corbel, RP Fender, AK Tzioumis, M Nowak, V McIntyre, P Durouchoux, R Sood

Abstract:

We report the results of a long-term campaign of radio, soft- and hard- X-ray observations of the galactic black hole candidate GX 339-4. In the Low-Hard X-ray state the system displays a strong 3-way linear correlation between soft-and hard-X-rays and radio emission, implying a coupling between the Comptonising corona and a radio-emitting compact jet. In this state the radio emission is linearly polarised at a level of around 2%, with an almost constant polarisation angle, indicative of a favored axis in this system probably related to the compact jet and/or black hole spin axis. In the Off X-ray state the radio emission declines with the X-ray emission to below detectable levels, suggesting that it is simply a lower-luminosity version of the Low-Hard state. In the High-Soft state both the hard-X-ray and radio emission are suppressed. We also note that the transitions from the Low-Hard state to the High-Soft state (and the reverse) are possibly associated with discrete ejection(s) of expanding relativistic plasma.