Soft X-ray emission lines in the X-ray binary Swift J1858.6-0814 observed with XMM-Newton-RGS: disc atmosphere or wind?

Abstract

We find soft X-ray emission lines from the X-ray binary Swift J1858.6-0814 in data from XMM-Newton-RGS: N VII, O VII and O VIII, as well as notable residuals short of a detection at Ne IX and other higher ionisation transitions. These could be associated with the disc atmosphere, as in accretion disc corona sources, or with a wind, as has been detected in Swift J1858.6-0814 in emission lines at optical wavelengths. Indeed, the N VII line is redshifted, consistent with being the emitting component of a P-Cygni profile. We find that the emitting plasma has an ionisation parameter $\log (\xi )=1.35\pm 0.2$ and a density $n>1.5\times 10^{11}$ cm${}^{-3}$. From this, we infer that the emitting plasma must be within $10^{13}$ cm of the ionising source, $\sim 5\times 10^7{r}_{\mathrm{g}}$ for a $1.4M_{\odot }$ neutron star, and from the line width that it is at least $10^4{r}_{\mathrm{g}}$ away ($2\times 10^9(M/1.4M_{\odot })$ cm). We compare this with known classes of emission line regions in other X-ray binaries and active galactic nuclei.

10 pages, 7 figures, MNRAS accepted

References in corpus (10)

• The magnetic nature of disk accretion onto black holes
• The Accretion Disk Wind in the Black Hole GRO J1655-40
• Size and properties of the narrow-line region in Seyfert-2 galaxies from spatially-resolved optical spectroscopy
• Spectrum Synthesis Modeling of the X-ray Spectrum of GRO J1655-40 Taken During the 2005 Outburst
• High Density Reflection Spectroscopy I. A case study of GX~339-4
• Accretion and Outflow in V404 Cyg
• NuSTAR observations of the Transient Galactic Black Hole Binary Candidate Swift J1858.6-0814: A New Sibling of V404 Cyg and V4641 Sgr?
• The variable radio counterpart of Swift J1858.6-0814
• Relativistic redshifts in quasar broad lines
• Profiles of spectral lines from failed and decelerated winds from neutron stars and black holes

Cited by in corpus (5)

• A persistent ultraviolet outflow from an accreting neutron star binary transient
• A shared accretion instability for black holes and neutron stars
• Dips and eclipses in the X-ray binary Swift J1858.6-0814 observed with NICER
• The complex spectral behavior of the newly discovered neutron star X-ray binary Swift J1858.6-0814
• X-ray Iron absorption line in Swift J1858.6-0814