A Monte Carlo Simulation of the Broad Band X-ray Emission of the Accreting Millisecond X-ray pulsar MAXI J1816-195

Fuente: arXiv
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Autores principales: You, Yuan, Zhang, Shuang-Nan, Li, Zhaosheng, Ge, Mingyu
Formato: Preprint
Publicado: 2024
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author You, Yuan
Zhang, Shuang-Nan
Li, Zhaosheng
Ge, Mingyu
author_facet You, Yuan
Zhang, Shuang-Nan
Li, Zhaosheng
Ge, Mingyu
contents MAXI J1816-195 is an accreting millisecond X-ray pulsar (AMXP) discovered in 2022. According to the Insight-HXMT data, the pulsations of this source extend all the way to over 100 keV, and its pulse profiles change from a single peak in low-energy range to double peaks in high-energy range. In this work, we simulate its energy spectra and pulse profiles with a Compton scattering Monte Carlo program. The simulation results suggest that the low energy X-ray source on the neutron star surface should be pencil-beamed radiations from the magnetic poles, and there should be a boundary layer in a hollow cylinder shape between the accretion disc and the neutron star surface: the up-scattering of the polar radiations in the boundary layer leads to the double peak structure of the high-energy pulse profile. Under this boundary layer geometry, we suggest that the rarity of AMXPs can be caused by the smearing of the boundary layer. To estimate the mass M and radius R of accretion-powered millisecond pulsars whose surface radiations are badly polluted by the accretion disk and boundary layer, the impact of Compton scattering in the boundary layer on the radiation should be removed before employing the X-ray pulse profile modeling method.
format Preprint
id arxiv_https___arxiv_org_abs_2403_16375
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Monte Carlo Simulation of the Broad Band X-ray Emission of the Accreting Millisecond X-ray pulsar MAXI J1816-195
You, Yuan
Zhang, Shuang-Nan
Li, Zhaosheng
Ge, Mingyu
High Energy Astrophysical Phenomena
MAXI J1816-195 is an accreting millisecond X-ray pulsar (AMXP) discovered in 2022. According to the Insight-HXMT data, the pulsations of this source extend all the way to over 100 keV, and its pulse profiles change from a single peak in low-energy range to double peaks in high-energy range. In this work, we simulate its energy spectra and pulse profiles with a Compton scattering Monte Carlo program. The simulation results suggest that the low energy X-ray source on the neutron star surface should be pencil-beamed radiations from the magnetic poles, and there should be a boundary layer in a hollow cylinder shape between the accretion disc and the neutron star surface: the up-scattering of the polar radiations in the boundary layer leads to the double peak structure of the high-energy pulse profile. Under this boundary layer geometry, we suggest that the rarity of AMXPs can be caused by the smearing of the boundary layer. To estimate the mass M and radius R of accretion-powered millisecond pulsars whose surface radiations are badly polluted by the accretion disk and boundary layer, the impact of Compton scattering in the boundary layer on the radiation should be removed before employing the X-ray pulse profile modeling method.
title A Monte Carlo Simulation of the Broad Band X-ray Emission of the Accreting Millisecond X-ray pulsar MAXI J1816-195
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2403.16375