Combining timing characteristics with physical broad-band spectral modelling of black hole X-ray binary GX 339-4
Abstract
GX 339-4 is a black hole X-ray binary that is a key focus of accretion studies, since it goes into outburst roughly every 2-3 yr. Tracking of its radio, infrared (IR), and X-ray flux during multiple outbursts reveals tight broad-band correlations. The radio emission originates in a compact, self-absorbed jet; however, the origin of the X-ray emission is still debated: jet base or corona? We fit 20 quasi-simultaneous radio, IR, optical, and X-ray observations of GX 339-4 covering three separate outbursts in 2005, 2007, 2010-2011, with a composite corona+jet model, where inverse Compton emission from both regions contributes to the X-ray emission. Using a recently proposed identifier of the X-ray variability properties known as power-spectral hue, we attempt to explain both the spectral and evolving timing characteristics, with the model. We find the X-ray spectra are best fit by inverse Compton scattering in a dominant hot corona (kTe ∼ hundreds of keV). However, radio and IR-optical constraints imply a non-negligible contribution from inverse Compton scattering off hotter electrons (kTe ≥ 511 keV) in the base of the jets, ranging from a few up to ∼50 per cent of the integrated 3-100 keV flux. We also find that the physical properties of the jet show interesting correlations with the shape of the broad-band X-ray variability of the source, posing intriguing suggestions for the connection between the jet and corona.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 2019
- DOI:
- 10.1093/mnras/stz604
- arXiv:
- arXiv:1902.10833
- Bibcode:
- 2019MNRAS.485.3696C
- Keywords:
-
- accretion;
- accretion discs;
- black hole physics;
- relativistic processes;
- galaxies: jets;
- X-rays: binaries;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Accepted for publication in MNRAS, 20 pages, 16 figures