First detection of X-ray polarization from the accreting neutron star 4U 1820-303

Abstract

This paper reports the first detection of polarization in the X-rays for atoll-source 4U 1820-303, obtained with the Imaging X-ray Polarimetry Explorer (IXPE) at 99.999% confidence level (CL). Simultaneous polarimetric measurements were also performed in the radio with the Australia Telescope Compact Array (ATCA). The IXPE observations of 4U 1820-303 were coordinated with Swift-XRT, NICER, and NuSTAR aiming to obtain an accurate X-ray spectral model covering a broad energy interval. The source shows a significant polarization above 4 keV, with a polarization degree of 2.0(0.5)% and a polarization angle of -55(7) deg in the 4-7 keV energy range, and a polarization degree of 10(2)% and a polarization angle of -67(7) deg in the 7-8 keV energy bin. This polarization also shows a clear energy trend with polarization degree increasing with energy and a hint for a position-angle change of about 90 deg at 96% CL around 4 keV. The spectro-polarimetric fit indicates that the accretion disk is polarized orthogonally to the hard spectral component, which is presumably produced in the boundary/spreading layer. We do not detect linear polarization from the radio counterpart, with a 99.97% upper limit of 50% at 7.25 GHz.

References in corpus (39)

• On the Absorption of X-rays in the Interstellar Medium
• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• CASA, the Common Astronomy Software Applications for Radio Astronomy
• The MAXI Mission on the ISS: Science and Instruments for Monitoring All Sky X-Ray Images
• The Swift/BAT Hard X-ray Transient Monitor
• The Two-Phase Pair Corona Model for Active Galactic Nuclei and X-ray Binaries: How to Obtain Exact Solutions
• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• An efficient photoelectric X-ray Polarimeter for the study of Black Holes and Neutron Stars
• Panchromatic study of GRB 060124: from precursor to afterglow
• ixpeobssim: a Simulation and Analysis Framework for the Imaging X-ray Polarimetry Explorer
• X-ray Polarization from Accreting Black Holes: Coronal Emission
• Accretion Disk Boundary Layers Around Neutron Stars: X-ray Production in Low-Mass X-ray Binaries
• Relativistic iron emission lines in neutron star low-mass X-ray binaries as probes of neutron star radii
• GRB 221009A, The BOAT
• Handling Background in IXPE polarimetric data
• 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
• Binary and Long-Term (Triple?) Modulations of 4U 1820$-$30 in NGC 6624
• Radio detections of the neutron star X-ray binaries 4U 1820-30 and Ser X-1 in soft X-ray states
• Polarized X-rays from windy accretion in Cygnus X-1
• A self-consistent approach to the hard and soft states of 4U 1705-44
• Time-Resolved Ultraviolet Observations of the Globular Cluster X-ray Source in NGC 6624: The Shortest Known Period Binary System
• Accretion geometry of the neutron star low mass X-ray binary Cyg X-2 from X-ray polarization measurements
• Testing reflection features in 4U 1705-44 with XMM-Newton, BeppoSAX and RXTE in the hard and soft state
• Discovery of strongly variable X-ray polarization in the neutron star low-mass X-ray binary transient XTE J1701$-$462
• X-ray polarimetry and spectroscopy of the neutron star low-mass X-ray binary GX 9+9: an in-depth study with IXPE and NuSTAR
• Polarization change due to fast winds from accretion disks
• The evolving polarised jet of black hole candidate Swift J1745-26
• Polarization properties of weakly magnetized Neutron Stars in Low Mass X-ray Binaries
• Polarization properties of the weakly magnetized neutron star X-ray binary GS 1826-238 in the high soft state
• Dependence of the orbital modulation of X-rays from 4U 1820-303 on the accretion rate
• On the nature of the flux variability during an expansion stage of a type I X-ray burst: Constraints on Neutron Star Parameters for 4U 1820-30
• INTEGRAL spectral variability study of the atoll 4U 1820-30: first detection of hard X-ray emission
• ALMA observations of 4U 1728-34 and 4U 1820-30: first detection of neutron star X-ray binaries at 300 GHz
• Study of the reflection spectrum of the LMXB 4U 1702-429
• Spectral state evolution of 4U~1820-30: the stability of the spectral index of Comptonization tail
• Spectro-polarimetric view of bright atoll source GX 9+9 using IXPE and AstroSat
• The evolving radio jet from the neutron star X-ray binary 4U 1820$-$30
• Broadband X-ray emission and the reality of the broad iron line from the Neutron Star - White Dwarf X-ray binary 4U 1820-30

Cited by in corpus (15)

• Highly Significant Detection of X-Ray Polarization from the Brightest Accreting Neutron Star Sco X-1
• X-Ray Polarized View on the Accretion Geometry in the X-Ray Binary Circinus X-1
• X-ray polarization from accretion disk winds
• 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
• Polarized radiation from the spreading layer of the weakly magnetized neutron stars
• X-ray spectro-polarimetric characterization of GX 340+0 in the horizontal branch: a highly inclined source?
• Characterization of High-polarization Stars and Blazars with DIPOL-1 at Sierra Nevada Observatory
• Constraining the geometry of the dipping atoll 4U 1624-49 with X-ray spectroscopy and polarimetry
• X-ray Dips and Polarization Angle Swings in GX 13+1
• 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
• First Detection of X-ray Polarization and Its Short-term Increase Pre- and Post-Eclipse in HMXB 4U 1700-377
• The NuSTAR view of Ultra-Compact X-ray Binaries
• X-ray polarization of Z-type neutron star low-mass X-ray binaries -- II. Spectropolarimetric analysis