X-ray Iron absorption line in Swift J1858.6-0814

Abstract

We present the spectral analysis of bright steady states in an outburst of the transient neutron star low-mass X-ray binary (NS-LMXB) Swift J1858.6-0814 observed with NICER. We detected an ionized iron K absorption line (H-like Fe) at 6.97keV in the spectrum. We estimated the photoionization parameter using the ratio of the equivalent widths (EWs) of the FeXXVI (H-like) (17+\-5eV) and FeXXV (He-like) (<3eV) and discuss the origin of the iron absorption line. The irradiated gas producing the absorption line would locate within (3-6)*1E9cm from the X-ray source. We suggest that the observed H-like Fe absorption line originates from the highly-ionized gas in the inner accretion disk in Swift J1858.6-0814.

6 pages, 5 figures

References in corpus (6)

• Spectral and temporal properties of Compton scattering by mildly relativistic thermal electrons
• Disk, Corona, Jet Connection in the Intermediate State of MAXI J1820+070 Revealed by NICER Spectral-Timing Analysis
• Discovery of thermonuclear (Type I) X-ray bursts in the X-ray binary Swift J1858.6-0814 observed with NICER and NuSTAR
• Dips and eclipses in the X-ray binary Swift J1858.6-0814 observed with NICER
• Soft X-ray emission lines in the X-ray binary Swift J1858.6-0814 observed with XMM-Newton-RGS: disc atmosphere or wind?
• X-ray Eclipse Mapping Constrains the Binary Inclination and Mass Ratio of Swift J1858.6-0814