XRISM High-Resolution X-ray Spectroscopy of Cygnus X-1 -- highly ionized Iron absorption structures
arXiv:2604.21497 · doi:10.1093/pasj/psaf104
Abstract
We present the first high-resolution X-ray spectral analysis of Cygnus X-1 using XRISM. The observation was carried out from April 7 to 10, 2024, covering the orbital phase range 0.65--0.17 during its low/hard state. Taking advantage of the exceptional energy resolution of the Resolve instrument, we examined highly ionized iron absorption lines and characterized the ionization states, column densities, and line-of-sight velocities of the absorbing plasma. Spectral analysis revealed an ionization parameter of approximately 3, column densities of a few times 10^21 cm^-2, and a blueshifted velocity of approximately 100 km s^-1. The observation was divided into two phases: before and after orbital phase phi_orb = 0.9, corresponding to non-dipping and dipping intervals. While only weak absorption features were present before phi_orb = 0.9, strong absorption by He-like and H-like Fe appeared during the dipping phase. We measured equivalent widths of 2.3 eV, 0.4 eV, and 1.2 eV for He-like Fe K-alpha, and H-like Ly-alpha1 and Ly-alpha2, respectively, demonstrating the capability of XRISM Resolve to securely detect narrow absorption features of only a few eV. These measurements trace the motion of the absorbing material and offer insight into the kinematics and spatial distribution of the wind in the vicinity of the black hole. These findings enhance our understanding of wind-fed accretion in Cygnus X-1 and highlight the importance of continued high-resolution X-ray observations to further constrain the physical properties of winds and accretion flows in high-mass X-ray binaries.
References in corpus (42)
- On the Absorption of X-rays in the Interstellar Medium
- X-ray Properties of Black-Hole Binaries
- Modelling the behaviour of accretion flows in X-ray binaries
- The MAXI Mission on the ISS: Science and Instruments for Monitoring All Sky X-Ray Images
- The Swift/BAT Hard X-ray Transient Monitor
- RXTE Observation of Cygnus X-1: II. Timing Analysis
- The Mass of the Black Hole in Cygnus X-1
- Cygnus X-1 contains a 21-solar mass black hole -- implications for massive star winds
- Gas Slit Camera (GSC) onboard MAXI on ISS
- Polarized x-rays constrain the disk-jet geometry in the black hole x-ray binary Cygnus X-1
- Orbital, precessional and flaring variability of Cygnus X-1
- Alternative explanations for extreme supersolar iron abundances inferred from the energy spectrum of Cygnus X-1
- Suzaku Results on Cygnus X-1 in the Low/Hard State
- Systematic comparison of photoionised plasma codes with application to spectroscopic studies of AGN in X-rays
- Superorbital variability of X-ray and radio emission of Cyg X-1 - II. Dependence of the orbital modulation and spectral hardness on the superorbital phase
- Chandra X-ray spectroscopy of the focused wind in the Cygnus X-1 system. I. The non-dip spectrum in the low/hard state
- Long term variability of Cygnus X-1 V. State definitions with all sky monitors
- 2D wind clumping in hot, massive stars from hydrodynamical line-driven instability simulations using a pseudo-planar approach
- The First High Resolution X-ray Spectrum of Cyg X-1: Soft X-Ray Ionization and Absorption
- The Distribution of X-ray Dips with Orbital Phase in Cygnus X-1
- Polarized X-rays from windy accretion in Cygnus X-1
- Using the X-ray Dust Scattering Halo of Cygnus X-1 to determine distance and dust distributions
- Revealing the Focused Companion Wind in Cygnus X-1 with Chandra
- Long term variability of Cygnus X-1: VII. Orbital variability of the focussed wind in Cyg X-1 / HDE 226868 system
- Data-oriented Diagnostics of Pileup Effects on the Suzaku XIS
- Chandra X-Ray Spectroscopy of the Focused Wind in the Cygnus X-1 System. II. The Nondip Spectrum in the Low/Hard State - Modulations with Orbital Phase
- Systematically Revisiting All NuSTAR Spins of Black Holes in X-Ray Binaries
- Chandra X-ray spectroscopy of the focused wind in the Cygnus X-1 system III. Dipping in the low/hard state
- The thermal-radiative wind in low mass X-ray binary H 1743-322: II. iron line predictions from Monte Carlo radiation transfer
- Breaking the spectral degeneracies in black hole binaries with fast timing data
- The doubling of the superorbital period of Cyg X-1
- Stellar wind in state transitions of high-mass X-ray binaries
- MAXI observations of long-term variations of Cygnus X-1 in the low/hard and the high/soft states
- Long term variability of Cygnus X-1. VIII. A spectral-timing look at low energies with NICER
- Dramatic Variability of X-ray Absorption Lines in the Black Hole Candidate Cygnus X-1
- Kinematic study of the association Cyg OB3 with Gaia DR2
- Probing the Inflow/Out-flow and Accretion Disk of Cyg X-1 in the High State with HETG/Chandra
- Comprehensive UV and Optical spectral analysis of Cygnus X-1: Stellar and wind parameters, abundances, and evolutionary implications
- Highly Ionized Fe-K Absorption Line from Cygnus X-1 in the High/Soft State Observed with Suzaku
- X-ray Variations at the Orbital Period from Cygnus X-1 in the High/Soft State
- Peering into the tilted heart of Cyg X-1 with high-precision optical polarimetry
- Formation of Wind-Fed Black Hole High-mass X-ray Binaries: The Role of Roche-lobe-Overflow Post Black-Hole Formation