Disk–wind Connection During the Heartbeats of GRS 1915+105

Abstract

Disk and wind signatures are seen in the soft state of Galactic black holes, while the jet is seen in the hard state. Here we study the disk-wind connection in the ρ class of variability in GRS 1915+105 using a joint NuSTARChandra observation. The source shows 50 s limit cycle oscillations. By including new information provided by the reflection spectrumand using phase-resolved spectroscopy, we find that the change in the inner disk inferred from the blackbody emission is not matched by reflection measurements. The latter is almost constant, independent of the continuum model. The two radii are comparable only if the disk temperature color correction factor changes, an effect that could be due to the changing opacity of the disk caused by changes in metal abundances. The disk inclination is similar to that inferred from the jet axis, and oscillates by ∼10°. The simultaneous Chandra data show the presence of two wind components with velocities between 500 and 5000 km s −1 , and possibly two more with velocities reaching 20,000 km s −1 (∼0.06 c). The column densities are ∼5×10 22 cm −2 . An upper limit to the wind response time of 2 s is measured, implying a launch radius of <6×10 10 cm. The changes in wind velocity and absorbed flux require the geometry of the wind to change during the oscillations, constraining the wind to be launched from a distance of 290-1300 r g from the black hole. Both data sets support fundamental model predictions in which a bulge originates in the inner disk and moves outward as the instability progresses.

A Statistical Analysis of the “Heartbeat” Behavior of GRS 1915+105

“…dynamical time and thermal/viscous time; but their correlation is unknown at the current stage. (3) It has been pointed out that the reflection component is prominent in the heartbeat state (Zoghbi et al 2016). The evolution trend of the disk component and the total Xray luminosity are insensitive to models with or without the reflection.…”

The luminosity dependence of thermally driven disc winds in low-mass X-ray binaries

“…Second, it exhibits extremely unusual spectral states and variability properties (e.g. Zoghbi et al 2016), quite different from the canonical low/hard and high/soft states seen in most LMXBs. Third, with an orbital period of 34 days (Casares & Jonker 2014), it is by far the largest known LMXB system and could therefore host a significantly larger accretion disc than we include in our model.…”

The reflection component in the average and heartbeat spectra of the black hole candidate IGR J17091-3642 during the 2016 outburst

“…Due to the existence of a reflection spectrum in the heartbeat state of IGR J17091, we can study the accretion geometry in this system and compare it to the case of GRS 1915+105. Using simultaneous NuSTAR and Chandra observations, Zoghbi et al (2016) carried out phase-resolved spectroscopy of the oscillations in the heartbeat state of GRS 1915+105. They extracted the NuSTAR spectra at six phases of the heartbeat QPO and fitted the spectra with the model tbabs*(ezdiskbb + relxill + cutoffpl + Gaussian), which is very similar to the model we used here for IGR J17091.…”

“…They extracted the NuSTAR spectra at six phases of the heartbeat QPO and fitted the spectra with the model tbabs*(ezdiskbb + relxill + cutoffpl + Gaussian), which is very similar to the model we used here for IGR J17091. Because IGR J17091 is much weaker than GRS 1915+105, the data we used for phase-resolved spectroscopy here cannot constrain the reflection parameters with the same accuracy as in the case of GRS 1915+105 presented by Zoghbi et al (2016). A reflection spectrum is produced by the power-law component irradiating the surface of the accretion disc, where the X-ray photons interact with the material producing diverse atomic features (e.g., George & Fabian 1991;Matt, Perola, & Piro 1991).…”