A Variable Ionized Disk Wind in the Black Hole Candidate EXO 1846-031
Abstract
After 34 yr, the black hole candidate EXO 1846-031 went into outburst again in 2019. We investigate its spectral properties in the hard intermediate and the soft states with NuSTAR and Insight-HXMT. A reflection component has been detected in the two spectral states but possibly originating from different illumination spectra: in the intermediate state, the illuminating source is attributed to a hard coronal component, which has been commonly observed in other X-ray binaries, whereas in the soft state, the reflection is probably produced by disk self-irradiation. Both cases support EXO 1846-031 as a low-inclination system of $\sim 40^\circ $ . An absorption line is clearly detected at ∼7.2 keV in the hard intermediate state, corresponding to a highly ionized disk wind ( $\mathrm{log}\,\xi \gt 6.1$ ) with a velocity of up to 0.06c. Meanwhile, quasi-simultaneous radio emissions have been detected before and after the X-rays, implying the coexistence of disk winds and jets in this system. If only the high-flux segment of the NuSTAR observation is considered, the observed wind appears to be magnetically driven. The absorption line disappeared in the soft state and a narrow emission line appeared at ∼6.7 keV on top of the reflection component, which may be evidence for disk winds, but data with higher spectral resolution are required to examine this.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 2021
- DOI:
- 10.3847/1538-4357/abc55e
- arXiv:
- arXiv:2010.14662
- Bibcode:
- 2021ApJ...906...11W
- Keywords:
-
- High energy astrophysics;
- X-ray transient sources;
- Accretion;
- 739;
- 1852;
- 14;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Accepted for publication in ApJ