Hard X-ray Quiescent Emission in Magnetars via Resonant Compton Upscattering
arXiv:1710.09017 · doi:10.1088/1742-6596/932/1/012021
Abstract
Non-thermal quiescent X-ray emission extending between 10 keV and around 150 keV has been seen in about 10 magnetars by RXTE, INTEGRAL, Suzaku, NuSTAR and Fermi-GBM. For inner magnetospheric models of such hard X-ray signals, inverse Compton scattering is anticipated to be the most efficient process for generating the continuum radiation, because the scattering cross section is resonant at the cyclotron frequency. We present hard X-ray upscattering spectra for uncooled monoenergetic relativistic electrons injected in inner regions of pulsar magnetospheres. These model spectra are integrated over bundles of closed field lines and obtained for different observing perspectives. The spectral turnover energies are critically dependent on the observer viewing angles and electron Lorentz factor. We find that electrons with energies less than around 15 MeV will emit most of their radiation below 250 keV, consistent with the turnovers inferred in magnetar hard X-ray tails. Electrons of higher energy still emit most of the radiation below around 1 MeV, except for quasi-equatorial emission locales for select pulse phases. Our spectral computations use a new state-of-the-art, spin-dependent formalism for the QED Compton scattering cross section in strong magnetic fields.
arXiv comment5 pages, 2 figures, to appear in Proc. "Physics of Neutron Stars - 2017," Journal of Physics: Conference Series, eds. G. G. Pavlov, et al., held in Saint Petersburg, Russia, 10-14 July, 2017
References in corpus (22)
- Magnetars
- The McGill Magnetar Catalog
- Gamma-Ray Observations of a Giant Flare from The Magnetar SGR 1806-20
- A giant, periodic flare from the soft gamma repeater SGR1900+14
- Magnetars: the physics behind observations
- Unifying the observational diversity of isolated neutron stars via magneto-thermal evolution models
- A Major SGR-like Outburst and Rotation Glitch in the No-Longer-So-Anomalous X-ray Pulsar 1E 2259+586
- On the mechanism of hard X-ray emission from magnetars
- Discovery of hard non-thermal pulsed X-ray emission from the anomalous X-ray pulsar 1E 1841-045
- Magnetars as persistent hard X-ray sources: INTEGRAL discovery of a hard tail in SGR 1900+14
- Resonant Cyclotron Scattering in Three Dimensions and the Quiescent Non-thermal X-ray Emission of Magnetars
- Resonant Compton Upscattering in Anomalous X-ray Pulsars
- The Quiescent Counterpart of the Soft Gamma-ray Repeater SGR 0526-66
- Detailed high-energy characteristics of AXP 4U 0142+61 - Multi-year observations with INTEGRAL, RXTE, XMM-Newton and ASCA
- Detection of the energetic pulsar PSR B1509-58 and its pulsar wind nebula in MSH 15-52 using the Fermi-Large Area Telescope
- Broad-band study with Suzaku of the magnetar class
- Compton Scattering in Ultra-Strong Magnetic Fields: Numerical and Analytical Behavior in the Relativistic Regime
- Particle-in-cell simulations of the twisted magnetospheres of magnetars
- Deep NuSTAR and Swift Monitoring Observations of the Magnetar 1E 1841-045
- Burst and Persistent Emission Properties during the Recent Active Episode of the Anomalous X-ray Pulsar 1E 1841-045
- Cooling Rates for Relativistic Electrons Undergoing Compton Scattering in Strong Magnetic Fields
- Compton scattering in strong magnetic fields: Spin-dependent influences at the cyclotron resonance