Probing magnetars magnetosphere through X-ray polarization measurements
arXiv:1311.7500 · doi:10.1093/mnras/stt2310
Abstract
The study of magnetars is of particular relevance since these objects are the only laboratories where the physics in ultra-strong magnetic fields can be directly tested. Until now, spectroscopic and timing measurements at X-ray energies in soft gamma-repeaters (SGRs) and anomalous X-ray pulsar (AXPs) have been the main source of information about the physical properties of a magnetar and of its magnetosphere. Spectral fitting in the ~ 0.5-10 keV range allowed to validate the "twisted magnetosphere" model, probing the structure of the external field and estimating the density and velocity of the magnetospheric currents. Spectroscopy alone, however, may fail in disambiguating the two key parameters governing magnetospheric scattering (the charge velocity and the twist angle) and is quite insensitive to the source geometry. X-ray polarimetry, on the other hand, can provide a quantum leap in the field by adding two extra observables, the linear polarization degree and the polarization angle. Using the bright AXP 1RXS J170849.0-400910 as a template, we show that phase-resolved polarimetric measurements can unambiguously determine the model parameters, even with a small X-ray polarimetry mission carrying modern photoelectric detectors and existing X-ray optics. We also show that polarimetric measurements can pinpoint vacuum polarization effects and thus provide an indirect evidence for ultra-strong magnetic fields.
12 pages, 8 figures, accepted for publication in MNRAS
References in corpus (18)
- Physics of Strongly Magnetized Neutron Stars
- The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars
- Corona of Magnetars
- Untwisting magnetospheres of neutron stars
- A variable absorption feature in the X-ray spectrum of a magnetar
- X-ray spectra from magnetar candidates. I. Monte Carlo simulations in the non-relativistic regime
- A Sealed Gas Pixel Detector for X-ray Astronomy
- Atmosphere Models of Magnetized Neutron Stars: QED Effects, Radiation Spectra, and Polarization Signals
- Distances to Anomalous X-ray Pulsars using Red Clump Stars
- Resonant cyclotron scattering in magnetars' emission
- Direct reading of charge multipliers with a self-triggering CMOS analog chip with 105k pixels at 50 micron pitch
- The fundamental plane for radio magnetars
- X-ray spectra from magnetar candidates. II Resonant cross sections for electron-photon scattering in the relativistic regime
- Topology of magnetars external field. I. Axially symmetric fields
- Low energy polarization sensitivity of the Gas Pixel Detector
- Swift and Chandra confirm the intensity-hardness correlation of the AXP 1RXS J170849.0-400910
- X-ray Polarimetry: a new window on the high energy sky
- POLARIX: a pathfinder mission of X-ray polarimetry
Cited by in corpus (32)
- Magnetars: the physics behind observations
- Science with e-ASTROGAM (A space mission for MeV-GeV gamma-ray astrophysics)
- Evidence for vacuum birefringence from the first optical polarimetry measurement of the isolated neutron star RX\, J1856.53754
- A High Braking Index for a Pulsar
- Polarization of neutron star surface emission: a systematic analysis
- General relativistic neutron stars with twisted magnetosphere
- X-Ray Polarimetry with the Polarization Spectroscopic Telescope Array (PolSTAR)
- X-ray spectra and polarization from magnetar candidates
- On the braking index of the unusual high-B rotation-powered pulsar PSR J1846-0258
- Predicting the X-ray polarization of type-2 Seyfert galaxies
- Physics and astrophysics of strong magnetic field systems with eXTP
- Probing magnetar emission mechanisms with spectropolarimetry
- Axisymmetric force-free magnetosphere in the exterior of a neutron star
- On the spectrum and polarization of magnetar flare emission
- A Study of background for IXPE
- Vacuum birefringence and the X-ray polarization from black-hole accretion disks
- Probing the clumping structure of Giant Molecular Clouds through the spectrum, polarisation and morphology of X-ray Reflection Nebulae
- Nonlinear QED effects in X-ray emission of pulsars
- On the polarization properties of magnetar giant flare pulsating tails
- Vacuum non-linear electrodynamic polarization effects in hard emission of pulsars and magnetars
- Instrumentation and Future Missions in the Upcoming Era of X-Ray Polarimetry
- Photon-axion mixing in thermal emission of isolated neutron stars
- Systematic Analysis of the Effects of Mode Conversion on Thermal Radiation from Neutron Stars
- Fitting XMM-Newton Observations of the AXP 1RXS J170849.0-400910 with four magnetar surface emission models, and predictions for X-ray polarization observations with IXPE
- Strongly pulsed thermal X-rays from a single extended hot spot on PSR J2021+4026
- X-ray polarimetry-timing
- X-ray polarisation signatures in bombarded magnetar atmospheres
- Pulsating ultraluminous X-ray sources: modeling the thermal emission and polarization properties
- Hard X-ray Polarimetry -- An overview of the method, science drivers and recent findings
- Statistical features of multiple Compton scattering in a strong magnetic field
- Resonant Inverse Compton Scattering and Hard X-ray Emission in Magnetar Magnetospheres
- Instruments for Focal Plane X-Ray Polarimetry in the Next Decade