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

Abstract

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.

Are Low-Frequency Quasi-Periodic Oscillations seen in accretion flows the disk response to a jet instability?

“…But, in any case, if some jet instability is to give rise to a LFQPO related to r J , it must involve the distant thus non-relativistic jet region. We thus neglect below the effect of the spine (see however Barnier et al 2022).…”

“…In our view, the role of the central spine in the whole outflow collimation remains to be assessed (see for instance Barnier et al 2022). The jet corresponds here to the super-FM Blandford-Payne outflow launched from the JED.…”

“…Hereafter, we focus on such a framework, the hybrid disk configuration proposed by Ferreira et al (2006b), which has been recently successfully confronted to observations in a series of papers (Marcel et al 2018b(Marcel et al ,a, 2019(Marcel et al , 2020(Marcel et al , 2022Ursini et al 2020;Marino et al 2020;Barnier et al 2022). In this framework, a large scale vertical magnetic field B z is assumed to thread the inner disk regions, say below 10 4 r g where r g = GM/c 2 is the gravitational radius.…”

Do radio active galactic nuclei reflect X-ray binary spectral states?

“…The XRB state transitions can in reality be much more complex than described here, often showing failed outbursts or rare transitions. Some sources went through an outburst cycle multiple times, such as GX 339-4 (Corbel et al 2013;Zdziarski et al 2004;Belloni et al 2005;Homan et al 2005;Barnier et al 2022), whereas others, such as Cyg X-1, never dropped to quiescence and are continuously fed by accretion (Esin et al 1998;Grinberg et al 2014;Čechura et al 2015). Overall, the cyclical outbursts of XRBs typically last from months to years (Fender et al 2004).…”

Do Radio Active Galactic Nuclei Reflect X-ray Binary Spectral States?

“…The XRB state transitions can be in reality much more complex than described here, often showing failed outbursts or rare transitions. Some sources went through an outburst cycle multiple times, such as GX 339-4 (Corbel et al 2013;Zdziarski et al 2004;Belloni et al 2005;Homan et al 2005;Barnier et al 2022). Whereas, others like Cyg X-1 never dropped to quiescence and are continuously fed by accretion (Esin et al 1998;Grinberg et al 2014;Čechura et al 2015).…”