Outburst Phase Research Articles

X-Ray Flashes on Helium Novae

A helium nova occurs on a white dwarf (WD) accreting hydrogen-deficient matter from a helium star companion. When the mass of a helium envelope on the WD reaches a critical value, unstable helium burning ignites to trigger a nova outburst. A bright soft X-ray phase appears in an early outbursting phase of a helium nova before it optically rises toward maximum. Such an X-ray bright phase is called the X-ray flash. We present theoretical light curves of X-ray flashes for 1.0, 1.2, and 1.35 M ☉ helium novae with mass accretion rates of (1.6–7.5) × 10−7 M ☉ yr−1. Long durations of the X-ray flashes (100 days–10 yr) and high X-ray luminosities (∼1038 erg s−1) indicate that X-ray flashes are detectable as a new type of X-ray transient or persistent X-ray sources. An X-ray flash is a precursor of optical brightening, so that the detection of X-ray flashes on helium novae enables us to plan arranged observation for optical premaximum phases that have been one of the frontiers of the study of novae. We found a candidate object of helium-burning X-ray flash from the literature on extragalactic X-ray surveys. This X-ray transient source is consistent with our X-ray flash model of a 1.35 M ⊙ WD.

Exploring the Archives: A Search for Novae in UVIT Snapshots of M31

Extensive multiwavelength studies of novae have been carried out in our galaxy and in M31 for decades. However, UV studies of extragalactic novae are limited, especially those in quiescence. For the first time, we present a UV catalog of novae in M31 using the archival AstroSat Ultraviolet Imaging Telescope (UVIT) imaging data. We used two image subtraction techniques to retrieve objects located deep into the M31 central region. We have found 42 novae in total in the UVIT images, 15 of which have been detected in multiple filters in the far-ultraviolet (FUV) and near-ultraviolet. The novae detected at quiescence show signatures of accretion disk from their UV spectral energy distributions, whereas those in the outburst phase show signatures of a pseudo-photosphere. A few novae were also detected in multiple epochs. Some show a near-constant FUV magnitude at quiescence, while others caught near the outburst reveal pre-eruption dips in their light curves. We conclude with a discussion on the significance of UV surveys in illuminating theoretical predictions for novae systems, including detecting the elusive early UV flash.

Study on microstructure and electrochemical corrosion behavior of ζ-FeZn13 phase layer in hot-dip galvanized coating

In this study, the electrochemical corrosion behavior of outburst and flat ζ-FeZn13 phase layers was investigated using scanning electron microscopy, field emission scanning electron microscopy, electrochemical workstation, and Raman spectroscopy instrument. The ζ phase layer is composed of the η phase, coarse ζ phase, and fine ζ phase. Their corrosion potential is Eη-Zn=-1.140±0.003 V, Efine-ζ=-1.052±0.003 V, and Ecoarse-ζ=-1.036±0.002 V. The presence of fine ζ phases can form a thick passivation film on the surface of the coating. The thickness of the passivation film for the outburst and flat ζ phase layers is 5.31 nm and 6.47 nm, respectively. The more uniform the distribution of fine ζ phases, the thicker the passivation film. The corrosion types of the outburst phase layer are mainly local corrosion and pitting corrosion, and the flat phase layer is mainly uniform corrosion. The corrosion products of η phase are ε-Zn(OH)2, 4Zn(OH)2.ZnCl2, Zn5(CO3)2(OH)6, and Zn5(Cl2)(OH)8.H2O. The corrosion products of ζ phase are Fe2O3, ZnO, and Zn(OH)2.

Discovery of evolving low-frequency QPOs in hard X-rays (∼100 keV) observed in black hole Swift J1727.8−1613 with AstroSat

ABSTRACT We report the first detection of evolving low-frequency quasi-periodic oscillation (LFQPO) frequencies in hard X-rays upto 100 keV with AstroSat/LAXPC during ‘unusual’ outburst phase of Swift J1727.8−1613 in hard intermediate state (HIMS). The observed LFQPO in 20–100 keV has a centroid $\nu _{_{\rm QPO}}=1.43$ Hz, a coherence factor Q = 7.14 and an amplitude ${\rm rms_{_{\rm QPO}}} = 10.95{{\ \rm per\ cent}}$ with significance σ = 5.46. Type-C QPOs (1.09–2.6 Hz) are found to evolve monotonically during HIMS of the outburst with clear detection in hard X-rays (80−100 keV), where ${\rm rms_{_{\rm QPO}}}$ decreases ($\sim 12\!-\!3{{\ \rm per\ cent}}$) with energy. Further, $\nu _{_{\rm QPO}}$ is seen to correlate (anticorrelate) with low- (high-) energy flux in 2–20 keV (15–50 keV). Wide-band (0.7−40 keV) energy spectrum of NICER/XTI and AstroSat/LAXPC is satisfactorily described by the ‘dominant’ thermal Comptonization contribution (∼88 per cent) in presence of a ‘weak’ signature of disc emissions (kTin ∼ 0.36 keV) indicating the harder spectral distribution. Considering source mass $M_{\rm BH}=10\, \mathrm{M}_\odot$ and distance 1.5 < d (kpc) < 5, the unabsorbed bolometric luminosity is estimated as $\sim 0.03\!-\!0.92{{\ \rm per\ cent}}\, L_{\rm Edd}$. Finally, we discuss the implications of our findings in the context of accretion dynamics around black hole X-ray binaries.

A possible third body in the X-ray system GRS 1747−312 and models with higher order multiplicity

ABSTRACT GRS 1747−312 is a bright Low-Mass X-ray Binary in the globular cluster Terzan 6, located at a distance of 9.5 kpc from the Earth. It exhibits regular outbursts approximately every 4.5 months, during which periodic eclipses are known to occur. These eclipses have only been observed in the outburst phase, and are not clearly seen when the source is quiescent. Recent Chandra observations of the source were performed in 2019 June and 2021 April, June, and August. Two of these observations captured the source during its outburst, and showed clear flux decreases at the expected time of eclipse. The other two observations occurred when the source was quiescent. We present the discovery of a dip that occurred during the quiescent state. The dip is of longer duration and its time of occurrence does not fit the ephemeris of the shorter eclipses. We study the physical characteristics of the dip and determine that it has all the properties of an eclipse by an object with a well defined surface. We find that there are several possibilities for the nature of the object causing the 5.3 ks eclipse. First, GRS 1747−312 may be an X-ray triple, with an LMXB orbited by an outer third object, which could be an M-dwarf, brown dwarf, or planet. Secondly, there could be two LMXBs in close proximity to each other, potentially bound together. Whatever the true nature of the eclipser, its presence suggests that the GRS 1747−312 system is exotic.

Study of Instabilities and Outbursts in the Luminous Blue Variables AF And and R 127

Luminous blue variables (LBVs) are evolved massive stars close to the Eddington limit, exhibiting distinct spectroscopic and photometric variability having unsteady mass-loss rates. These stars undergo considerable changes in their surface temperature from quiescent to outburst phases. The cause of this irregular variability and unsteady mass-loss rate is not fully understood. Here we present the results of a linear stability analysis in two LBVs AF And and R 127 during their quiescent and outburst phases. We observe that several modes are unstable in the models of the considered LBVs, with mode interaction being common in the modal diagrams for the models of both LBVs. For AF And, the number of instabilities increases in models with temperature below 15000 K. These found instabilities may be linked to the observed irregular variabilities and surface eruptions. The observational facilities of the BINA network will be highly beneficial for studying the spectroscopic and photometric behaviour of the considered LBVs.

Ejection of porous dust–ice agglomerates from the surface of the cometary nucleus

This paper presents two problems related to the ejection of particles from the surface of the cometary nucleus. The first problem is related to the phase of quiet sublimation. This part of the paper discusses the influence of the water ice sublimation flux on the size of particles that are lifted into the coma. In these considerations, three formulas were used to describe the water ice sublimation flux. The calculations show that the size of the particle lifted into the coma depends on its density and the sublimation flux of water ice. The second mechanism is related to the cometary outburst phase. In this part of the paper, it was proposed that the cometary outburst as a high-energy process may significantly contribute to explaining the presence of small particles in the coma. Based on the calculations performed, it was shown that the dimensions of these particles depend on the adopted value of the power index in the power law. Based on the considerations presented in this paper, the presence of both large and fine dust particles observed in the coma during the Rosetta mission can be explained.

Fast infrared winds during the radio-loud and X-ray obscured stages of the black hole transient GRS 1915+105

The black hole transient GRS 1915+105 entered a new phase of activity in 2018, generally characterised by low X-ray and radio fluxes. This phase has only been interrupted by episodes of strong and variable radio emission, where high levels of X-ray absorption local to the source were measured. We present 18 epochs of near-infrared spectroscopy (2018–2023) obtained with GTC/EMIR and VLT/X-shooter, spanning both radio-loud and radio-quiet periods. We demonstrate that radio-loud phases are characterised by strong P-Cygni line profiles, indicative of accretion disc winds with velocities of up to ∼3000 km s−1. This velocity is consistent with those measured in other black hole transients. It is also comparable to the velocity of the X-ray winds detected during the peak outburst phases in GRS 1915+105, reinforcing the idea that massive, multi-phase outflows are characteristic features of the largest and most powerful black hole accretion discs. Conversely, the evolution of the Brγ line profile during the radio-quiet phases follows the expected trend for accretion disc lines in a system that is gradually decreasing its intrinsic luminosity, exhibiting weaker intensities and more pronounced double-peaks.

High-soft to Low-hard State Transition in Black Hole X-Ray Binaries with GRMHD Simulations

To understand the decaying phase of outbursts in the black hole (BH) X-ray binaries (BH-XRBs), we performed very long general relativistic magnetohydrodynamic simulations of a geometrically thin accretion disk around a Kerr BH with slowly rotating matter injected from outside. We thoroughly studied the flow properties, dynamical behavior of the accretion rate, magnetic flux rate, and jet properties during the temporal evolution. Due to the interaction between the thin disk and injected matter, the accretion flow near the BH goes through different phases. The sequence of phases is: soft state → soft-intermediate state → hard-intermediate state → hard state → quiescent state. For the accretion rate (and hence the luminosity) to decrease (as observed) in our model, the mass injection should not decay slower than the angular momentum injection. We also observed quasiperiodic oscillations (QPOs) in the accretion flow. Throughout the evolution, we observed low-frequency QPOs (∼10 Hz) and high-frequency QPOs (∼200 Hz). Our simple unified accretion flow model for state transitions is able to describe outbursts in BH-XRBs.

MAXI J1348–630: Estimating the black hole mass and binary inclination using a scaling technique

The multi-wavelength outburst activity in the recently discovered X-ray binary transient MAXI J1348–630 has sparked a great deal of controversy about the characteristics of this binary and questions around whether the source contains a black hole (BH). Here, we present the results of our analysis of the outburst of MAXI J1348–630 using Swift/XRT data. We find that energy spectra in all spectral states can be modeled using a combination of Comptonization and Gaussian iron-line components. In addition, we show that the X-ray photon index, Γ, is correlated with the mass accretion rate, Ṁ. We find that Γ increases monotonically with Ṁ from the low-hard state to the high-soft state, and then becomes saturated at Γ∼ 3. This index behavior is similar to that exhibited by a number of other BH candidates. This result represents observational evidence of the presence of a BH in MAXI J1348–630. We also show that the value of Γ is correlated with the quasi periodic oscillation frequency, νL. Based on this correlation, we applied a scaling method to estimate a BH mass of 14.8 ± 0.9 M⊙, using the well-studied BH binary XTE J1550–564 as a reference source. The recent discovery of a giant dust scattering ring around MAXI J1348–630 by SRG/eROSITA has refined distance estimates to this X-ray source. With this distance, we were able to estimate the disk inclination i = (65 ± 7)° using the scaling technique for the correlation between Γ and normalization proportional to Ṁ. We detected a specific behavior of the disk seed photon temperature, kTs, immediately before the outburst: kTs initially decreases from 0.4 to 0.2 keV and increases only after the source transits to the outburst rise-maximum phase. An initial decrease in kTs occurred simultaneously with an increase in the illumination fraction, f. We interpreted this effect in terms of the bulk motion Comptonization model. At the start of the outburst, the Compton cloud (or “corona”) is very extended and, thus, the seed photons injected to the corona from the relatively far-away disk region, where kTs is about 0.2–0.4 keV. While Ṁ increases (or luminosity increases), the corona contracts, thus increasing the seed photon temperature, kTs. It is possible that such a decrease in kTs occurring simultaneously with an increase in the illumination fraction, f, can be considered a signature of the readiness of a BH object to go into an outburst phase.

Properties of luminous red supergiant stars in the Magellanic Clouds

Context. There is evidence that some red supergiants (RSGs) experience short-lived phases of extreme mass loss, producing copious amounts of dust. These episodic outburst phases help strip the hydrogen envelope from evolved massive stars, drastically affecting their evolution. However, to date, the observational data of episodic mass loss is limited. Aims. This paper aims to derive surface properties of a spectroscopic sample of 14 dusty sources in the Magellanic Clouds using the Baade telescope. These properties can be used for future spectral energy distribution fitting studies to measure the mass-loss rates from present circumstellar dust expelled from the star through outbursts. Methods. We applied MARCS models to obtain the effective temperature (Teff) and extinction (AV) from the optical TiO bands. We used a χ2 routine to determine the model that best fits the obtained spectra. We computed the Teff using empirical photometric relations and compared this to our modelled Teff. Results. We have identified a new yellow supergiant and spectroscopically confirmed eight new RSGs and one bright giant in the Magellanic Clouds. Additionally, we observed a supergiant B[e] star and find that the spectral type has changed compared to previous classifications, confirming that the spectral type is variable over decades. For the RSGs, we obtained the surface and global properties, as well as the extinction (AV). Conclusions. Our method has picked up eight new, luminous RSGs. Despite selecting dusty RSGs, we find values for AV that are not as high as expected given the circumstellar extinction of these evolved stars. The most remarkable object from the sample, LMC3, is an extremely massive and luminous evolved massive star and may be grouped amongst the largest and most luminous RSGs known in the Large Magellanic Cloud (log(L*/L⊙) ~ 5.5 and R = 1400 R⊙).

Addressing the dichotomy of fishing and climate in fishery management with the FishClim model

The relative influence of fishing and Climate-Induced Environmental Change (CIEC) on long-term fluctuations in exploited fish stocks has been controversial1–3 because separating their contributions is difficult for two reasons. Firstly, there is in general, no estimation of CIEC for a pre-fishing period and secondly, the assessment of the effects of fishing on stocks has taken place at the same time as CIEC4. Here, we describe a new model we have called FishClim that we apply to North Sea cod from 1963 to 2019 to estimate how fishing and CIEC interact and how they both may affect stocks in the future (2020-2100) using CMIP6 scenarios5. The FishClim model shows that both fishing and CIEC are intertwined and can either act synergistically (e.g. the 2000-2007 collapse) or antagonistically (e.g. second phase of the gadoid outburst). Failure to monitor CIEC, so that fisheries management immediately adjusts fishing effort in response to environmentally-driven shifts in stock productivity, will therefore create a deleterious response lag that may cause the stock to collapse. We found that during 1963-2019, although the effect of fishing and CIEC drivers fluctuated annually, the pooled influence of fishing and CIEC on the North Sea cod stock was nearly equal at ~55 and ~45%, respectively. Consequently, the application of FishClim, which quantifies precisely the respective influence of fishing and climate, will help to develop better strategies for sustainable, long-term, fish stock management.

29P/Schwassmann–Wachmann 1: A Rosetta Stone for Amorphous Water Ice and CO ↔ CO2 Conversion in Centaurs and Comets?

Centaur 29P/Schwassmann–Wachmann 1 (SW1) is a highly active object orbiting in the transitional “Gateway” region between the Centaur and Jupiter-family comet (JFC) regions. SW1 is unique among the Centaurs in that it experiences quasi-regular major outbursts and produces CO emission continuously; however, the source of the CO is unclear. We argue that, due to its very large size (∼32 km radius), SW1 is likely still responding, via amorphous water ice (AWI) conversion to crystalline water ice (CWI), to the “sudden” change in its external thermal environment produced by its Myrs-long dynamical migration from the Kuiper Belt to its current location at the inner edge of the Centaur region. It is this conversion process that is the source of the abundant CO and dust released from the object during its quiescent and outburst phases. If correct, these arguments have a number of important predictions testable via remote sensing and in situ spacecraft characterization, including the quick release on Myr timescales of CO from AWI conversion for any few kilometer-scale scattered disk Kuiper Belt Objects transiting into the inner system; that to date SW1 has only converted between 50% and 65% of its nuclear AWI to CWI; that volume changes on AWI conversion could have caused subsidence and cave-ins, but not significant mass wasting or crater loss; that SW1's coma should contain abundant amounts of CWI+CO2 “dust” particles; and that when SW1 transits into the inner system within the next 10,000 yr, it will be a very different kind of JFC.

A Light-curve Analysis of the X-Ray Flash First Observed in Classical Novae

An X-ray flash, expected in a very early phase of a nova outburst, was at last detected with the SRG/eROSITA in the classical nova YZ Reticuli 2020. The observed flash timescale, luminosity, and blackbody temperature substantially constrain the nova model. We present light-curve models of the X-ray flash for various white dwarf (WD) masses and mass-accretion rates. We have found the WD mass in YZ Ret to be as massive as M WD ∼ 1.3 M ☉ with mass-accretion rates of yr−1, including the case where the mass-accretion rate is changing between them, consistent with the SRG/eROSITA observation. The X-ray observation confirms the luminosity to be close to the Eddington limit at the X-ray flash. The occurrence of optically thick winds, with the photospheric radius exceeding ∼0.1 R ☉, terminated the X-ray flash of YZ Ret by strong absorption. This sets a constrain on the starting time of wind mass loss. A slight contamination of the hydrogen-rich envelope by the core material seems to be preferred to explain the very short duration of the X-ray flash.

Physics of nova outbursts: A theoretical model of classical nova outbursts with self-consistent wind mass loss

Abstract We present a model for one cycle of a classical nova outburst based on a self-consistent wind mass loss accelerated by the gradient of radiation pressure, i.e., so-called optically thick winds. Evolution models are calculated by a Henyey code for a 1.0 $M_{\odot }$ white dwarf with a mass-accretion rate of 5 × 10−9 $M_{\odot }$ yr−1. The outermost part of the hydrogen-rich envelope is connected to a steadily moving envelope where optically thick winds occur. We confirm that no internal shock waves occur at thermonuclear runaway. The wind mass-loss rate reaches a peak of 1.4 × 10−4 $M_{\odot }$ yr−1 at the epoch of the maximum photospheric expansion, where the photospheric temperature decreases to log Tph (K) = 3.90. Almost all of the accreted mass is lost in the wind. The nuclear energy generated in hydrogen burning is lost in a form of photon emission (64%), gravitational energy (lifting up the wind matter against gravity, 35%), and the kinetic energy of the wind (0.23%). A classical nova should be very bright in a far-UV (100–300 Å) band for one day just after the onset of thermonuclear runaway (∼ 25 d before the optical maximum). In the decay phase of the nova outburst, the envelope structure is very close to that of a steady-state solution.

Optical and X-Ray Observations of MAXI J1820+070 During the Early Outburst Phase in 2018: Zooming in the Low Frequency QPOs* *Supported by the National Natural Science Foundation of China.

We report a further investigation of the optical low frequency quasi periodic oscillations (LF QPOs) detected in the black hole transient MAXI J1820+070 in the 2018 observations with the YFOSC mounted on Lijiang 2.4 m telescope (LJT). In addition, we make use of the Insight-HXMT/HE observations to measure the properties of the quasi-simultaneous X-ray LF QPOs of MAXI J1820+070 on the same day. We compared the centroid frequency, the full width at half maximum (FWHM) and the fractional rms of the LF QPOs in both wavelength ranges. We found that the centroid frequency of the optical QPO is at a frequency of 51.58 mHz, which is consistent with that of the X-ray LF QPO detected on the same day within 1 mHz. We also found that the FWHM of the optical LF QPO is significantly smaller than that of the X-ray LF QPO, indicating that the optical QPO has a higher coherence. The quasi-simultaneous optical and the X-ray LF QPO at a centroid frequency of about 52 mHz suggests that the actual mechanisms of these LF QPOs as the Lense–Thirring precession should work in the vicinity of a radius of about 80–117 gravitational radii (R g = GM/c 2, M is the mass of the black hole) from the black hole if the QPO frequency is related to a proxy of the orbital frequency in the accretion flow as the Lense–Thirring precession model suggests. Furthermore, the apparent higher coherence of the optical QPO favors that it is a more original signal as compared with the X-ray QPO.

Plateaus, dips, and rebrightenings during the outbursts of WZ Sge: no magnetic propeller, but a veiling curtain

ABSTRACT WZ Sge is the prototype of highly evolved, low-accretion rate dwarf novae (DNe). During the decline from eruptions, its light curve displays a ‘dip’ followed by ≃10 ‘echo outbursts’. The standard disc instability model does not account for this behaviour, which is also seen in other low-accretion rate DNe. One recent interpretation for these rapid brightness changes is that they represent transitions into and out of a magnetic propeller regime. Here, we test this scenario with time-resolved, ultraviolet spectroscopy taken with the Hubble Space Telescope just before, during and after the dip in WZ Sge’s 2001 eruption. We find no distinctive or unique signatures that could be attributed to a propeller in either the time-averaged UV spectrum or the variability spectrum. Thus the data do not support the magnetic propeller scenario. Instead of resolving the mystery of WZ Sge’s outburst light curve, our study has actually added another: the origin of the narrow absorption features seen in all outburst phases. We show explicitly that these features are likely formed in a high-density ‘veiling curtain’ with a characteristic temperature $\rm T \simeq 17,000~\mathrm{K}$. However, the nature and origin of this veil are unclear. Given that WZ Sge-type DNe are the most intrinsically common class of accreting white dwarfs, resolving these questions should be a high priority.

Discovery of a Short-period and Unusually Helium-deficient Dwarf Nova KSP-OT-201701a by the KMTNet Supernova Program

Abstract We present the first ever discovery of a short-period and unusually helium-deficient dwarf nova KSP-OT-201701a by the Korea Microlensing Telescope Network Supernova Program. The source shows three superoutbursts, each led by a precursor outburst, and several normal outbursts in BVI during the span of ∼2.6 yr with supercycle and normal cycle lengths of about 360 and 76 days, respectively. Spectroscopic observations near the end of a superoutburst reveal the presence of strong double-peaked H i emission lines together with weak He i emission lines. The helium-to-hydrogen intensity ratios measured by He i λ5876 and Hα lines are 0.10 ± 0.01 at a quiescent phase and 0.26 ± 0.04 at an outburst phase, similar to the ratios found in long-period dwarf novae, while significantly lower than those in helium cataclysmic variables (He CVs). Its orbital period of 51.91 ± 2.50 minutes, which is estimated based on time-series spectroscopy, is a bit shorter than the superhump period of 56.52 ± 0.19 minutes, as expected from the gravitational interaction between the eccentric disk and the secondary star. We measure its mass ratio to be 0.37 − 0.21 + 0.32 using the superhump period excess of 0.089 ± 0.053. The short orbital period, which is under the period minimum, the unusual helium deficiency, and the large mass ratio suggest that KSP-OT-201701a is a transition object evolving to an He CV from a long-period dwarf nova with an evolved secondary star.

Gaia 20eae: A Newly Discovered Episodically Accreting Young Star

Abstract The Gaia Alert System issued an alert on 2020 August 28, on Gaia 20eae when its light curve showed a ∼4.25 magnitude outburst. We present multiwavelength photometric and spectroscopic follow-up observations of this source since 2020 August and identify it as the newest member of the FUor/EXor family of sources. We find that the present brightening of Gaia 20eae is not due to the dust-clearing event but due to an intrinsic change in the spectral energy distribution. The light curve of Gaia 20eae shows a transition stage during which most of its brightness (∼3.4 mag) has occurred on a short timescale of 34 days with a rise rate of 3 mag/month. Gaia 20eae has now started to decay at a rate of 0.3 mag/month. We have detected a strong P Cygni profile in Hα, which indicates the presence of winds originating from regions close to the accretion. We find signatures of very strong and turbulent outflow and accretion in Gaia 20eae during this outburst phase. We have also detected a redshifted absorption component in all of the Ca ii IR triplet lines consistent with a signature of hot infalling gas in the magnetospheric accretion funnel. This enables us to constrain the viewing angle with respect to the accretion funnel. Our investigation of Gaia 20eae points toward magnetospheric accretion being the phenomenon for the current outburst.

Clues on jet behavior from simultaneous radio-X-ray fits of GX 339-4

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.