Context. We proposed in paper I that the spectral evolution of transient X-ray binaries (XrB) is due to an interplay between two flows: a standard accretion disk (SAD) in the outer parts and a jet-emitting disk (JED) in the inner parts. We showed in papers II, III, and IV that the spectral evolution in X-ray and radio during the 2010–2011 outburst of GX 339-4 can be recovered. However, the observed variability in X-ray was never addressed in this framework. Aims. We investigate the presence of low frequency quasi-periodic oscillations (LFQPOs) during an X-ray outburst, and address the possible correlation between the frequencies of these LFQPOs and the transition radius between the two flows, rJ. Methods. We select X-ray and radio data that correspond to 3 outbursts of GX 339-4. We use the method detailed in Paper IV to obtain the best parameters rJ(t) and ṁin(t) for each outburst. We also independently search for X-ray QPOs in each selected spectra and compare the QPO frequency to the Kepler and epicyclic frequencies of the flow in rJ. Results. We successfully reproduce the correlated evolution of the X-ray spectra and the radio emission for 3 different activity cycles of GX 339-4. We use a unique normalisation factor for the radio emission, f∼R. We also report the detection of 7 new LFQPOs (3 Type B, and 4 Type C), to go along with the ones previously reported in the literature. We show that the frequency of Type C QPOs can be linked to the dynamical JED-SAD transition radius rJ, rather than to the optically thin-thick transition radius in the disk. The scaling factor q such that νQPO ≃ νK(rJ)/q is q ≃ 70 − 130, a factor consistent during the 4 cycles, and similar to previous studies. Conclusions. The JED-SAD hybrid disk configuration not only provides a successful paradigm allowing us to describe XrB cycles, but also matches the evolution of QPO frequencies. Type C QPOs provide an indirect way to probe the JED-SAD transition radius, where an undetermined process produces secular variability. The demonstrated relation between the transition radius links Type C QPOs to the transition between two different flows, effectively tying it to the inner magnetized structure, i.e., the jets. This direct connection between the jets’ (accretion-ejection) structure and the process responsible for Type C QPOs, if confirmed, could naturally explain their puzzling multi-wavelength behavior.

Context. X-ray binaries in outburst typically show two canonical X-ray spectral states (i.e., hard and soft states), as well as different intermediate states, in which the physical properties of the accretion flow are known to change. However, the truncation of the optically thick disk and the geometry of the optically thin accretion flow (corona) in the hard state are still debated. Recently, the JED-SAD paradigm has been proposed for black hole X-ray binaries, aimed at addressing the topic of accretion and ejection and their interplay in these systems. According to this model, the accretion flow is composed of an outer standard Shakura-Sunyaev disk (SAD) and an inner hot jet emitting disk (JED). The JED produces both hard X-ray emission, effectively playing the role of the hot corona, and radio jets. The disruption of the JED at the transition to the soft state coincides with the quenching of the jet. Aims. In this paper we use the JED-SAD model to describe the evolution of the accretion flow in the black hole transient MAXI J1820+070 during its hard and hard-intermediate states. Unlike the previous applications of this model, the Compton reflection component has been taken into account. Methods. We use eight broadband X-ray spectra, including NuSTAR, NICER, and the Neil Gehrels Swift Observatory data, providing a total spectral coverage of 0.8–190 keV. The data were directly fitted with the JED-SAD model. We performed the procedure twice, considering two different values for the innermost stable circular orbit (ISCO): 4 RG (a* = 0.55) and 2 RG (a* = 0.95). Results. Our results suggest that the optically thick disk (the SAD) does not extend down to the ISCO in any of the considered epochs. In particular, assuming RISCO = 4 RG, as the system evolves toward the transitional hard-intermediate state, we find an inner radius within a range of ∼60 RG in the first observation down to ∼30 RG in the last one. The decrease of the inner edge of the SAD is accompanied by an increase in the mass-accretion rate. However, when we assume RISCO = 2 we find that the mass accretion rate remains constant and the evolution of the accretion flow is driven by the decrease in the sonic Mach number mS, which is unexpected. In all hard–intermediate state observations, two reflection components, characterized by different values of ionization, are required to adequately explain the data. These components likely originate from different regions of the SAD. Conclusions. The analysis performed provides a coherent physical evolution of the accretion flow in the hard and hard-intermediate states and supports a truncated disk scenario. We show that a flared outer disk could, in principle, explain the double reflection component. The odd results obtained for RISCO = 2 RG can also be considered as further evidence that MAXI J1820+070 harbors a moderately spinning black hole, as suggested in other works.

Understanding the mechanisms of accretion-ejection during X-ray binary (XrB) outbursts has been a problem for several decades. For instance, it is still not clear what controls the spectral evolution of these objects from the hard to the soft states and then back to the hard states at the end of the outburst, tracing the well-known hysteresis cycle in the hardness-intensity diagram. Moreover, the link between the spectral states and the presence or absence of radio emission is still highly debated. In a series of papers we developed a model composed of a truncated outer standard accretion disk (SAD, from the solution of Shakura and Sunyaev) and an inner jet emitting disk (JED). In this paradigm, the JED plays the role of the hot corona while simultaneously explaining the presence of a radio jet. Our goal is to apply for the first time direct fitting procedures of the JED-SAD model to the hard states of four outbursts of GX 339-4 observed during the 2000–2010 decade by RXTE, combined with simultaneous or quasi simultaneous ATCA observations. We built JED-SAD model tables usable in XSPEC, as well as a reflection model table based on the XILLVER model of XSPEC. We applied our model to the 452 hard state observations obtained with RXTE/PCA. We were able to correctly fit the X-ray spectra and simultaneously reproduce the radio flux with an accuracy better than 15%. We show that the functional dependency of the radio emission on the model parameters (mainly the accretion rate and the transition radius between the JED and the SAD) is similar for all the rising phases of the different outbursts of GX 339-4, but it is significantly different from the functional dependency obtained in the decaying phases. This result strongly suggests a change in the radiative and/or dynamical properties of the ejection between the beginning and the end of the outburst. We discuss possible scenarios that could explain these differences.

Blueshifted X-ray absorption lines (preferentially from Fe XXV and Fe XXVI present in the 6–8 keV range) indicating the presence of massive hot disk winds in black hole (BH) X-ray binaries (XrB) are most generally observed during soft states. It has been recently suggested that the nondetection of such hot wind signatures in hard states could be due to the thermal instability of the wind in the ionization domain consistent with Fe XXV and Fe XXVI. Studying the wind thermal stability does require, however, a very good knowledge of the spectral shape of the ionizing spectral energy distribution (SED). In this paper, we discuss the expected evolution of the disk wind properties during an entire outburst by using the RXTE observations of GX 339-4 during its 2010–2011 outburst. While GX 339-4 never showed signatures of a hot wind in the X-rays, the dataset used is optimal for the analysis shown in this study. We computed the corresponding stability curves of the wind using the SED obtained with the jet-emitting disk model. We show that the disk wind can transit from stable to unstable states for Fe XXV and Fe XXVI ions on a day timescale. While the absence of wind absorption features in hard states could be explained by this instability, their presence in soft states seems to require changes in the wind properties (e.g., density) during the spectral transitions between hard and soft states. We propose that these changes could be partly due to the variation of the heating power release at the accretion disk surface through irradiation by the central X-ray source. The evolution of the disk wind properties discussed in this paper could be confirmed through the daily monitoring of the spectral transition of a high-inclination BH XrB.

The spectral evolution of transient X-ray binaries can be reproduced by an interplay between two flows separated at a transition radius RJ: a standard accretion disk (SAD) in the outer parts beyond RJ and a jet-emitting disk (JED) in the inner parts. In the previous papers in this series we successfully recover the spectral evolution in both X-rays and radio for four outbursts of GX 339-4 by playing independently with the two parameters: RJ and the disk accretion rate Ṁin. In this paper we compare the temporal evolution of both RJ and Ṁin for the four outbursts. We show that despite the undeniable differences between the time evolution of each outburst, a unique pattern in the Ṁin−RJ plane seems to be followed by all cycles within the JED-SAD model. We call this pattern a fingerprint, and show that even the “failed” outburst considered follows it. We also compute the radiative efficiency in X-rays during the cycles and consider its impact on the radio–X-ray correlation. Within the JED-SAD paradigm, we find that the accretion flow is always radiatively efficient in the hard states, with between 15% and 40% of the accretion power being radiated away at any given time. Moreover, we show that the radiative efficiency evolves with the accretion rate because of key changes in the JED thermal structure. These changes give birth to two different regimes with different radiative efficiencies: the thick disk and the slim disk. While the existence of these two regimes is intrinsically linked to the JED-SAD model, we show direct observational evidence of the presence of two different regimes using the evolution of the X-ray power-law spectral index, a model-independent estimate. We then argue that these two regimes could be the origin of the gap in X-ray luminosity in the hard state, the wiggles, and different slopes seen in the radio–X-ray correlation, and even the existence of outliers.