X-ray Dips and Polarization Angle Swings in GX 13+1

Abstract

We present the result from the April 2024 observation of the low-mass X-ray binary GX 13+1 with the Imaging X-ray Polarimetry Explorer (IXPE), together with NICER and Swift-XRT coordinated observations. Two light curve dips were observed; during them, the harder Comptonized spectral component was dominant and the polarization degree higher than in the softer, off-dip intervals. Through a joint analysis of the three IXPE observations, which also included the dip from the first observation, we demonstrate that the polarization properties varied in response to the intensity and spectral hardness changes associated with the dips. The polarization degree attained values up to ~4%. The polarization angle showed a swing of ~70° across the dip and off-dip states, comparable to the continuous rotation seen during the first IXPE observation. We discuss these results in the context of models for polarized emission from the accretion disk and the boundary/spreading layer on the neutron star surface. We also draw attention to the role that an extended accretion disk corona or disk wind can play in generating high polarization degrees and, possibly, swings of the polarization angle.

References in corpus (40)

• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• On the Absorption of X-rays in the Interstellar Medium
• The Formation and Structure of a Strongly Magnetized Corona above Weakly Magnetized Accretion Disks
• Stingray: A Modern Python Library For Spectral Timing
• Panchromatic study of GRB 060124: from precursor to afterglow
• ixpeobssim: a Simulation and Analysis Framework for the Imaging X-ray Polarimetry Explorer
• Accretion Disk Boundary Layers Around Neutron Stars: X-ray Production in Low-Mass X-ray Binaries
• Spectral changes during dipping in low-mass X-ray binaries due to highly-ionized absorbers
• Handling Background in IXPE polarimetric data
• Infrared spectroscopy of low-mass X-ray binaries II
• Spectra of the spreading layers on the neutron star surface and constraints on the neutron star equation of state
• A weighted analysis to improve the X-ray polarization sensitivity of IXPE
• A highly-ionized absorber in the X-ray binary 4U 1323-62: a new explanation for the dipping phenomenon
• XMM-Newton observations of GX 13+1: correlation between photoionised absorption and broad line emission
• Spin frequency distributions of binary millisecond pulsars
• Accretion geometry of the neutron star low mass X-ray binary Cyg X-2 from X-ray polarization measurements
• Discovery of a 57-69 Hz quasi-periodic oscillation in GX13+1
• Polarization of X-ray emission from the Sgr B2 cloud
• Discovery of strongly variable X-ray polarization in the neutron star low-mass X-ray binary transient XTE J1701$-$462
• X-ray polarimetry and spectroscopy of the neutron star low-mass X-ray binary GX 9+9: an in-depth study with IXPE and NuSTAR
• Chandra X-ray spectroscopy of a clear dip in GX 13+1
• Highly Significant Detection of X-Ray Polarization from the Brightest Accreting Neutron Star Sco X-1
• Analytical techniques for polarimetric imaging of accretion flows in Schwarzschild metric
• Peculiar spectral and power spectral behaviour of the LMXB GX 13+1
• First detection of X-ray polarization from the accreting neutron star 4U 1820-303
• The Disk Wind in the Neutron Star Low-mass X-Ray Binary GX 13+1
• Chandra and XMM Observations of the ADC Source 0921-630
• Discrete X-ray Signatures of a Photoionized Plasma Above the Accretion Disk of the Neutron Star EXO 0748-676
• High-Resolution X-Ray Spectroscopy of the Accretion Disk Corona Source 4U 1822-37
• Discovery of periodic dips in the light curve of GX 13+1: the X-ray orbital ephemeris of the source
• X-ray polarisation properties of thermal-radiative disc winds in binary systems
• Relativistic X-Ray Reflection and Photoionised Absorption in the Neutron-Star Low-Mass X-ray Binary GX 13+1
• X-Ray Polarized View on the Accretion Geometry in the X-Ray Binary Circinus X-1
• Modelling the disk atmosphere of the low mass X-ray binary EXO 0748-676
• Properties of the 24 Day Modulation in GX 13+1 from Near-Infrared and X-ray Observations
• Discovery of a strong rotation of the X-ray polarization angle in the galactic burster GX 13+1
• New polarimetric study of the galactic X-ray burster GX 13+1
• X-ray spectro-polarimetric characterization of GX 340+0 in the horizontal branch: a highly inclined source?
• Red-skewed K$\alpha$ iron lines in GX 13+1

Cited by in corpus (4)

• Polarized radiation from the spreading layer of the weakly magnetized neutron stars
• X-ray spectropolarimetric characterization of the Z-source GX 340+0 in the normal branch
• IXPE view of the Sco-like source GX 349+2 in the normal branch
• The detection of high X-ray polarization from an accretion disc corona source and its modelling via Monte Carlo radiation transfer simulation