Going with the Flow: Can the Base of Jets Subsume the Role of Compact Accretion Disk Coronae?

By S. Markoff, Michael A. Nowak, J. Wilms. 2005

478 citations recorded by the source corpus.

The hard state of X-ray binaries (XRBs) is characterized by a power-law spectrum in the X-ray band and a flat/inverted radio/IR spectrum associated with occasionally imaged compact jets. It has generally been thought that the hard X-rays result from Compton upscattering of thermal accretion disk photons by a hot, coronal plasma whose properties are inferred via spectral fitting. Interestingly, these properties—especially those from certain magnetized corona models—are very similar to the derived plasma conditions at the jet footpoints. Here we explore the question of whether the "corona" and "jet base" are in fact related, starting by testing the strongest premise that they are synonymous. In such models, the radio through the soft X-rays are dominated by synchrotron emission, while the hard X-rays are dominated by inverse Compton at the jet base—with both disk and synchrotron photons acting as seed photons. The conditions at the jet base fix the conditions along the rest of the jet, thus creating a direct link between the X-ray and radio emission. We also add to this model a simple iron line and convolve the spectrum with neutral reflection. After forward-folding the predicted spectra through the detector response functions, we compare the results to simultaneous radio/X-ray data obtained from the hard states of the Galactic XRBs GX 339-4 and Cygnus X-1. Results from simple Compton corona model fits are also presented for comparison. We demonstrate that the jet model fits are statistically as good as the single-component corona model X-ray fits, yet are also able to address the simultaneous radio data.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/6408ed1f8713770571125dad03ec60e6e5158616

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Citations in the corpus

XMM–Newton observations of the brightest ultraluminous X-ray sources (2006, background): “It also seems unlikely that the power-law emission could arise from processes at the base of a jet, as these are typically represented by much harder photon indices than measured here (Γ∼1.5–2; Markoff et al. 2005 and references therein).”
Accretion states and radio loudness in active galactic nuclei: analogies with X-ray binaries (2006, background): “However, it is also possible that the compact jet may contribute to the X-ray emission or even dominate it (Markoff, Falcke & Fender 2001; Markoff, Nowak & Wilms 2005).”
A quasi-periodic modulation of the iron line centroid energy in the black hole binary H1743−322 (2016, background): “Alternatively, the hot electrons may be located in a corona above the disc (e.g. Galeev et al. 1979; Haardt & Maraschi 1991) or at the base of a jet (e.g. Markoff, Nowak & Wilms 2005), or perhaps some combination of these alternatives.”
The role of the reflection fraction in constraining black hole spin (2014, background): “If this source is associated with the base of a jet (Markoff & Nowak 2004), besides the steep emissivity, this so called “lamp post” geometry is also able to explain the spectral connection of the X-ray andr - dio radiation (e.g., Markoff, Nowak & Wilms 2005; Maitra et al. 2009).”
Rapid optical and X-ray timing observations of GX 339-4: multi-component optical variability in the low/hard state (2010, background): “…have successfully modelled the optical power and broad-band spectrum as a result of (cyclo-)synchrotron emission, though the location and characteristics of the emitting plasm remain a matter of debate (e.g. Merloni et al. 2000; Esin et al. 2001; Markoff et al. 2005; Yuan et al. 2005, and more).”
Formation of precessing jets by tilted black hole discs in 3D general relativistic MHD simulations (2017, background): “If the jet base is X-ray bright (Markoff, Nowak & Wilms 2005), the precession can lead to quasi-periodic swings in the X-ray polarization angle in addition to those expected from the inner disc alone (Ingram et al. 2015).”
First X-ray-based statistical tests for clumpy-torus models: eclipse events from 230 years of monitoring of Seyfert AGN (2014, background): “…X-ray continuum in Seyferts is generally thought to originate via inverse Compton scattering of the soft UV photons from the accretion disk by hot electrons in a compact corona, possibly located in the innermost accretion disk or at the base of a jet (e.g., Haardt et al. 1997; Markoff et al. 2005).”
Modelling the behaviour of accretion flows in X-ray binaries (2007, background): “The base of the jet expands at weakly relativistic speeds, and the resulting weak beaming away from the disc is similar to that proposed by Beloborodov (1999), though the model of Markoff et al. (2005) has this in the centre of a truncated disc.”
Evaluating Spectral Models and the X-Ray States of Neutron Star X-Ray Transients (2007, background): “The inverse Compton spectrum could then arise from the base of the jet, and synchrotron emission would contribute seed photons and perhaps a secondary contribution to the X-ray spectrum (Markoff et al. 2005).”
Black hole accretion discs in the canonical low‐hard state (2009, background): “…law comes from either a patchy corona, possibly powered by magnetic flares (Beloborodov 1999; Di Matteo, Celotti & Fabian 1999; Merloni, Di Matteo & Fabian 2000; Merloni & Fabian 2001) or the base of a centrally located jet (Merloni & Fabian 2002; Markoff & Nowak 2004; Markoff, Nowak & Wilms 2005).”