Differentiating Neutron Star Models by X-Ray Polarimetry

Lu, Jiguang; Xu, R. X.; Feng, Hua

doi:10.1088/0256-307x/30/5/059501

Cited by 6 publications

(6 citation statements)

References 21 publications

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“…Future observations (e.g. X-ray polarimetry [52]) may more clearly show which is closer to the truth, the magnetar model or the fallback disk model.…”

Section: Fallback Disk Model As An Alternative To the Magnetospheric mentioning

confidence: 68%

Pulsar braking: magnetodipole vs. wind

Tong

2015

Sci. China Phys. Mech. Astron.

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Pulsars are good clocks in the universe. One fundamental question is that why they are good clocks? This is related to the braking mechanism of pulsars. Nowadays pulsar timing is done with unprecedented accuracy. More pulsars have braking indices measured. The period derivative of intermittent pulsars and magnetars can vary by a factor of several. However, during pulsar studies, the magnetic dipole braking in vacuum is still often assumed. It is shown that the fundamental assumption of magnetic dipole braking (vacuum condition) does not exist and it is not consistent with the observations. The physical torque must consider the presence of the pulsar magnetosphere. Among various efforts, the wind braking model can explain many observations of pulsars and magnetars in a unified way. It is also consistent with the up-to-date observations. It is time for a paradigm shift in pulsar studies: from magnetic dipole braking to wind braking. As one alternative to the magnetospheric model, the fallback disk model is also discussed. Tong H. Pulsar braking: magnetodipole vs. wind.

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“…Future observations (e.g. X-ray polarimetry [52]) may more clearly show which is closer to the truth, the magnetar model or the fallback disk model.…”

Section: Fallback Disk Model As An Alternative To the Magnetospheric mentioning

confidence: 68%

Pulsar braking: magnetodipole vs. wind

Tong

2015

Sci. China Phys. Mech. Astron.

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“…The model presented in this paper could be tested by future X-ray polarimetry, with which one may eventually differentiate compact star models as already discussed in Lu et al (2013). When X-rays propagate across the magnetosphere of an NS, there are two independent linear polarization eigenmodes: the ordinary mode (O-mode, the electric field is in the plane of the wave vector and the magnetic field) and the extraordinary mode (E-mode, perpendicular to the plane).…”

Section: X-ray Polarization Of Xdinsmentioning

confidence: 97%

The Optical/UV Excess of X-Ray-dim Isolated Neutron Stars. I. Bremsstrahlung Emission from a Strangeon Star Atmosphere

Wang

Tong

et al. 2017

ApJ

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X-ray dim isolated neutron stars (XDINSs) are characterized by Planckian spectra in X-ray bands, but show optical/ultraviolet(UV) excesses which are the measured photometry exceeding that is extrapolated from X-ray spectra. To solve this problem, a radiative model of bremsstrahlung emission from a plasma atmosphere is established in the regime of strangeon star. A strangeon star atmosphere could simply be regarded as the upper layer of a normal neutron star. This plasma atmosphere, formed and maintained by the ISM-accreted matter due to the so-called strangeness barrier, is supposed to be of two-temperature. All the seven XDINS spectra could be well fitted by the radiative model, from optical/UV to X-ray bands. The fitted radiation radii of XDINSs are from 7 to 13 km, while the modelled electron temperatures are between 50 and 250 eV, except RX J0806.4-4123 with a radiation radius ∼ 3.5 km, indicating that this source could be a low-mass strangeon star candidate. This strangeon star model could further be tested by soft X-ray polarimetry, such as the Lightweight Asymmetry and Magnetism Probe which is expected to work on Chinese space station around 2020.

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“…The high thermal conductivity on the surface of quark stars due to degenerated electrons indicates that photons of the two modes will have the same temperature. Therefore, thermal emission from the surface of bare quark stars will be almost zero polarized, 23 and soft X-ray polarimetry will enable us to discover bare quark stars if they exist.…”

Section: Thermal Emission From the Surface Of Pulsarsmentioning

confidence: 99%

LAMP: a micro-satellite based soft x-ray polarimeter for astrophysics

et al. 2015

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The Lightweight Asymmetry and Magnetism Probe (LAMP) is a micro-satellite mission concept dedicated for astronomical X-ray polarimetry and is currently under early phase study. It consists of segmented paraboloidal multilayer mirrors with a collecting area of about 1300 cm 2 to reflect and focus 250 eV X-rays, which will be detected by position sensitive detectors at the focal plane. The primary targets of LAMP include the thermal emission from the surface of pulsars and synchrotron emission produced by relativistic jets in blazars. With the expected sensitivity, it will allow us to detect polarization or place a tight upper limit for about 10 pulsars and 20 blazars. In addition to measuring magnetic structures in these objects, LAMP will also enable us to discover bare quark stars if they exist, whose thermal emission is expected to be zero polarized, while the thermal emission from neutron stars is believed to be highly polarized due to plasma polarization and the quantum electrodynamics (QED) effect. Here we present an overview of the mission concept, its science objectives and simulated observational results.

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Differentiating Neutron Star Models by X-Ray Polarimetry

Cited by 6 publications

References 21 publications

Pulsar braking: magnetodipole vs. wind

Pulsar braking: magnetodipole vs. wind

The Optical/UV Excess of X-Ray-dim Isolated Neutron Stars. I. Bremsstrahlung Emission from a Strangeon Star Atmosphere

LAMP: a micro-satellite based soft x-ray polarimeter for astrophysics

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