Work

Pulse-phase resolved variability of the X-ray pulsar RX J0440.9+4431 with SRG /ART-XC

Year: 2025

Type: article

Abstract: ABSTRACT We present a new method of accurate measurements for the pulse-phase-resolved power spectrum. We apply this method to the observation of X-ray pulsar RX J0440.9+4431 obtained during its supercritical accretion episode by the Mikhail Pavlinsky ART-XC X-ray telescope onboard the SRG observatory. We demonstrate that the power spectrum is composed of low- and high-frequency components which are not only well separated in frequency, but also show a very different dependence on the pulse phase. The behaviour of the low-frequency stochastic variability can be explained by the effect of changes in the rate of feeding the accretion columns near the pulsar surface from the disc far away. The high-frequency stochastic variability component should be associated with a different source of instability, plausibly operating at the base of accretion columns.

Source: Monthly Notices of the Royal Astronomical Society

DOI: 10.1093/mnras/staf2020

Authors: A N Semena, I A Mereminskiy, A S Gorban, S V Molkov, A A Lutovinov, A A Vikhlinin

Institutions: Russian Academy of Sciences, Space Research Institute, Center for Astrophysics Harvard & Smithsonian

Language: English

Topic: Astrophysical Phenomena and Observations

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,046

Funders: Ministry of Science and Higher Education of the Russian Federation, Russian Academy of Sciences