We analyse the 2021 outburst from black hole X-ray binary GX339-4 observed by NICER around hard to soft transition, when system exhibits flip-flops between two distinct luminosity states: a bright state with 5-6 Hz quasi-periodic oscillation (QPO) and dim showing only strong broadband noise. Despite marked differences in variability patterns these states, spectral energy distributions remain strikingly similar, minor changes body component range. find that QPO frequency correlates count...

It has been suggested that the cycles of activity X-ray Binaries (XrB) are triggered by a switch in dominant disk torque responsible for accretion (paper I). As rate increases, innermost regions would change from jet-emitting (JED) to standard (SAD). While JEDs have proven successfully reproduce hard states II), existence an outer cold SAD introduces extra non local cooling term. We investigate thermal structure and associated spectra such hybrid configuration. use 2T plasma code elaborated...

We elaborate on the paradigm proposed in Ferreira et al. (2006), where increase and decrease disk accretion rate is accompanied by a modification of magnetization $\mu \propto B_z^2/\dot{m}_{in}$, which turn determines dominant torque allowing accretion. For $\mu>0.1$, flow produces jets that vertically, carry away angular momentum (jet-emitting or JED). The goal this paper to investigate spectral signatures JED configurations. have developed two-temperature plasma code computes local...

Transients XrB exhibit different spectral shapes during their evolution. In luminosity-color diagrams, X-ray behavior forms unexplained q-shaped cycles. We proposed a framework where the innermost regions of accretion disk evolve as response to variations imposed in outer regions. These lead not only modifications inner rate $\dot m_{in}$ but also evolution transition radius $r_J$ between two The outermost region is standard (SAD), whereas jet-emitting (JED) all angular momentum carried away...

We test the two-corona accretion scenario for active galactic nuclei in case of `bare' Seyfert 1 galaxy HE 1143-1810. perform a detailed study broad-band UV--X-ray spectral properties and short-term variability. present results joint XMM-Newton NuSTAR monitoring source, consisting 5x20 ks observations, each separated by 2 days, performed December 2017. The source is variable flux among different correlation observed between UV X-ray emission. Moderate variability soft band. time-averaged...

We analyze seven NICER and NuSTAR epochs of the black hole X-ray binary GX 339-4 in hard state during its two most recent hard-only outbursts 2017 2019. These observations cover 1-100 keV unabsorbed luminosities between 0.3% 2.1% Eddington limit. With NICER's negligible pile-up, high count rate unprecedented time resolution, we perform a spectral-timing analysis spectral modeling using relativistic distant reflection models. Our fitting shows that as inner disk radius moves inwards, thermal...

After 26 years in outburst, the black hole X-ray binary GRS 1915+105 dimmed considerably early 2018; its flux dropped sharply mid-2019, and it has remained faint ever since. This period, "obscured state," is punctuated by occasional flares, many of which have been observed NICER as part our regular monitoring program. Here we present detailed time-resolved spectroscopy one bright flare, whose spectrum shows evidence high column density partial covering absorption extremely deep lines...

The spectral evolution of transient X-ray binaries can be reproduced by an interplay between two flows separated at a transition radius R J : standard accretion disk (SAD) in the outer parts beyond and jet-emitting (JED) inner parts. In previous papers this series we successfully recover both X-rays radio for four outbursts GX 339-4 playing independently with parameters: rate Ṁ . paper compare temporal outbursts. We show that despite undeniable differences time each outburst, unique pattern...

X-ray irradiation heating of accretion discs in black hole binaries (BHXBs) plays a key role regulating their outburst cycles. However, despite decades theoretical and observational efforts, the physical mechanism(s) responsible for irradiating these remains largely unknown. We have built an observationally-based methodology to estimate strength BHXB by combining multiwavelength optical/IR data throughout transient outbursts. apply this $\sim15$ yrs activity Galactic GX339$-$4. Our findings...

We proposed that the spectral evolution of transient X-ray binaries (XrB) is due to an interplay between two flows: a standard accretion disk (SAD) in outer parts and jet-emitting (JED) inner parts. showed previous papers radio during 2010-2011 outburst GX339-4 can be recovered. now investigate presence low frequency quasi-periodic oscillations (LFQPOs) outburst, address possible correlation frequencies these LFQPOs transition radius flows, rJ. select data form 3 outbursts GX339-4. use...

The timing properties of X-ray binaries are still not understood, particularly the presence quasi-periodic oscillations (QPOs) in their power spectra. solid-body regime Lense-Thirring precession is one prominent model invoked to explain most common type QPOs, Type C. However, requires a specific structure that has been examined light constrained accretion flows. We assume this paper, as requires, disk separated into two flows at transition radius $r_t$: cold outer flow and hot inner (playing...

Low Frequency Quasi-Periodic Oscillations or LF QPOs are ubiquitous in BH X-ray binaries and provide strong constraints on the accretion-ejection processes. Although several models have been proposed so far, none has proven to reproduce all observational no consensus emerged yet. We make conjecture that disks threaded by a large scale vertical magnetic field splits it into two radial zones. In inner Jet Emitting Disk (JED), near equipartition allows drive powerful self-collimated jets, while...

Context. X-ray binaries in outburst typically show two canonical spectral states (i.e., hard and soft states), as well different intermediate states, which the physical properties of accretion flow are known to change. However, truncation optically thick disk geometry thin (corona) state still debated. Recently, JED-SAD paradigm has been proposed for black hole binaries, aimed at addressing topic ejection their interplay these systems. According this model, is composed an outer standard...

Blueshifted X-ray absorption lines (preferentially from Fe XXV and XXVI present in the 6-8 keV range) indicating presence of massive hot disk winds Black Hole (BH) binaries (XrB) are most generally observed during soft states. It has been recently suggested that non-detection such wind signatures hard states could be due to thermal instability ionisation domain consistent with XXVI. Studying stability requires however a very good knowledge spectral shape ionizing Spectral Energy Distribution...

In our self-similar, analytical, magneto-hydrodynamic (MHD) accretion-ejection solution, the density at base of outflow is explicitly dependent on disk accretion rate - a unique property this class solutions. We had earlier found that ejection index $p >\sim 0.1 (\dot{M}_{acc} \propto r^p ) $ key MHD parameter decides if flow can cause absorption lines in high resolution X-ray spectra black hole binaries. Here we choose 3 dense warm solutions with = 0.1, 0.3, 0.45$ and carefully develop...

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 spectral evolution these objects from hard to soft states and then back at end outburst, tracing well-known hysteresis cycle in hardness-intensity diagram. Moreover, link between presence or absence radio emission highly debated. In series papers we developed model composed truncated outer standard accretion disk...

ABSTRACT The high-frequency bump, characterized by a frequency exceeding ∼30 Hz, represents seldom-explored time-variability feature in the power density spectrum (PDS) of black-hole X-ray binaries. In 2002, 2004, 2007, and 2010 outbursts GX 339 − 4, bump has been occasionally observed conjunction with type-C quasi-periodic oscillations (QPOs). We systematically study properties during these four Rossi Timing Explorer (RXTE) 2–60 keV bands detect 39 observations. While frequencies QPOs are...

X-ray binaries (XRBs) exhibit spectral hysteresis for luminosities in the range $10^{-2}\lesssim L/L_\mathrm{Edd}\lesssim 0.3$, with a hard state that persists from quiescent up to $\gtrsim 0.3L_\mathrm{Edd}$, transitioning soft survives decreasing down $\sim 10^{-2}L_\mathrm{Edd}$. We present possible approach explain this behavior based on thermal properties of magnetically arrested disk simulation. By post-processing simulation include radiative effects, we solve all equilibrium solutions...

X-ray binaries (XRBs) exhibit a spectral hysteresis for luminosities in the range $10^ L/L_ Edd 0.3$, with hard state that persists from quiescent up to $ 0.3L_ $, transitioning soft survives decreasing down L_ We present possible approach explain this behavior based on thermal properties of magnetically arrested disk simulation. By post-processing simulation include radiative effects, we solved all equilibrium solutions as accretion rate, M varies during XRB outburst. For an assumed scaling...

The non linear correlation between the UV and X-ray emission observed in Active Galactic Nuclei remains a puzzling question that challenged accretion models. While originates from cold disk, is emitted by hot corona whose physical characteristics geometry are still highly debated. Jet Emitting Disk - Standard Accretion (JED-SAD) spectral model stemming self similar accretion-ejection solutions. It composed of an inner magnetized flow launching jets, JED, outer SAD. has been successfully...