Orbital variability of polarized X-ray radiation reflected from a companion star in X-ray binaries

Abstract

The reflection of X-ray radiation produced near a compact object from its stellar companion contributes to the orbital variability of polarization in X-ray binaries. The X-rays are reflected mainly via Thomson scattering resulting in a high polarization. The orbital variability of the polarization strongly depends on the inclination and the orbital parameters allowing us to constrain them. To explore this phenomenon, we present analytical single-scattering models for the polarized reflection. We find that while diluted by the direct emission, the reflection can produce a polarization degree of about 1$\%$ in the case of a large reflection albedo. We fitted the orbital variations of the X-ray polarization observed by the Imaging X-ray Polarimetry Explorer from an accreting weakly magnetized neutron star `clocked burster' GS 1826$-$238 and found that the amplitude of the variations is too large to be primarily caused by the companion star. The polarized reflection is more significant if the compact object is obscured from the observer, and thus it should be more easily observable in certain high-inclination targets.

arXiv comment8 pages, 10 figures, submitted to A&A

References in corpus (24)

• emcee: The MCMC Hammer
• Precessing warped accretion discs in X-ray binaries
• Polarized x-rays constrain the disk-jet geometry in the black hole x-ray binary Cygnus X-1
• A New Dynamical Model for the Black Hole Binary LMC X-1
• Spectral changes during dipping in low-mass X-ray binaries due to highly-ionized absorbers
• Analytic models for albedos, phase curves and polarization of reflected light from exoplanets
• The 35-Day Evolution of the Hercules X-1 Pulse Profile: Evidence For A Resolved Inner Disk Occultation of the Neutron Star
• Polarized reflected light from the exoplanet HD189733b: First multicolor observations and confirmation of detection
• Determination of X-ray pulsar geometry with IXPE polarimetry
• The X-ray polarimetry view of the accreting pulsar Cen X-3
• Cygnus X-3 revealed as a Galactic ultraluminous X-ray source by IXPE
• Multi-epoch X-ray burst modelling: MCMC with large grids of 1D simulations
• Polarization properties of the weakly magnetized neutron star X-ray binary GS 1826-238 in the high soft state
• X-ray polarimetry of X-ray pulsar X Persei: another orthogonal rotator?
• X-ray pulsar GRO J1008$-$57 as an orthogonal rotator
• IXPE observations of the quintessential wind-accreting X-ray pulsar Vela X-1
• Complex variations of X-ray polarization in the X-ray pulsar LS V +44 17/RX J0440.9+4431
• X-ray polarimetry of the accreting pulsar GX 301-2
• Orbital variability of the optical linear polarization of the $\gamma$-ray binary LS I +61 303 and new constraints on the orbital parameters
• New polarimetric study of the galactic X-ray burster GX 13+1
• Reproductions of super-orbital X-ray light-curves with the precessing accretion ring model and implications on accretion flows through accretion rings
• High-precision broad-band linear polarimetry of early-type binaries I. Discovery of variable, phase-locked polarization in HD 48099
• Peering into the tilted heart of Cyg X-1 with high-precision optical polarimetry
• High-precision broadband linear polarimetry of early-type binaries IV. Binary system of DH Cephei in the open cluster of NGC 7380

Cited by in corpus (3)

• Variability of X-ray polarization of Cyg X-1
• Exploring polarization and geometry in the X-ray pulsar 4U 1538-52
• First Detection of X-ray Polarization and Its Short-term Increase Pre- and Post-Eclipse in HMXB 4U 1700-377