J 2025

Modulation of X-Ray Flux by Obscuration of Neutron Star Boundary Layer

TÖRÖK, Gabriel; Kateřina KLIMOVIČOVÁ; Debora LANČOVÁ; Monika MATUSZKOVÁ; Eva ŠRÁMKOVÁ et al.

Basic information

Original name

Modulation of X-Ray Flux by Obscuration of Neutron Star Boundary Layer

Authors

TÖRÖK, Gabriel; Kateřina KLIMOVIČOVÁ; Debora LANČOVÁ; Monika MATUSZKOVÁ; Eva ŠRÁMKOVÁ; Martin URBANEC; Miljenko ČEMELJIĆ; René ŠPRŇA and Vladimír KARAS

Edition

Astrophysical Journal, GB - Spojené království Velké Británie a, 2025, 0004-637X

Other information

Language

English

Type of outcome

Article in a journal

Field of Study

10308 Astronomy

Country of publisher

United Kingdom of Great Britain and Northern Ireland

Confidentiality degree

is not subject to a state or trade secret

References:

URL

Impact factor

Impact factor: 5.400 in 2024

Organization unit

Institute of physics in Opava

DOI

https://doi.org/10.3847/1538-4357/adad71

UT WoS

001427563300001

EID Scopus

2-s2.0-85219032655

Keywords in English

quasi periodic oscillations;integrated relativistic tori; black hole; epicyclic oscillations;axisymetrical modes; accreation tori;light curves;mass;binares;disk

Tags

RIV26, SGS-25-2024, SGS-31-2023, UF

Tags

International impact, Reviewed

Links

GN25-16928O, research and development project. GX21-06825X, research and development project.
Changed: 26/1/2026 09:23, Mgr. Pavlína Jalůvková

Abstract

In the original language

The quasiperiodic oscillations (QPOs) observed in the X-ray variability of both black hole (BH) and neutron star (NS) systems provide a tool for probing strong gravity and dense matter equations of state. Nevertheless, the mechanism of QPO modulation in NS systems, where the amplitudes of QPOs with frequencies approaching the kHz range are very high in comparison to BH high-frequency QPOs, remains an unsolved puzzle. Relativistic ray tracing of photons emitted from the immediate vicinity of compact objects has, to date, been used to investigate various mechanisms that explain the observed weak BH QPOs. However, it has not been applied to model the NS QPO signal, which requires incorporating the NS surface and a bright boundary layer (BL) on it. Here, we explore the QPO modulation mechanisms based on the BL obscuration. Using simplified models of axisymmetric oscillations of thick accretion disks (tori), we demonstrate that the disk oscillations drive the high NS QPO amplitudes through BL obscuration, which is relevant, especially for vertical oscillations. We also demonstrate that obscuration effects enable the observability of the Keplerian frequency in the case of disks that decay due to instabilities.
Displayed: 30/1/2026 05:28