A1 Refereed original research article in a scientific journal
Losing a minute every two years: SRG X-ray view of the rapidly accelerating X-ray pulsar SXP 1323
Authors: Mereminskiy IA, Mushtukov AA, Lutovinov AA, Tsygankov SS, Semena AN, Molkov SV, Shtykovsky AE
Publisher: EDP SCIENCES S A
Publication year: 2022
Journal: Astronomy and Astrophysics
Journal name in source: ASTRONOMY & ASTROPHYSICS
Journal acronym: ASTRON ASTROPHYS
Article number: A33
Volume: 661
Number of pages: 5
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202141813
Web address : https://doi.org/10.1051/0004-6361/202141813
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/176204650
The source SXP 1323 is a peculiar high-mass X-ray binary located in the Small Magellanic Cloud. It is renowned for its rapid spin-up. We investigate for the first time broadband X-ray properties of SXP 1323 as observed by the Mikhail Pavlinsky ART-XC and eROSITA telescopes on board the Spectrum-Roentgen-Gamma observatory. Using ART-XC and eROSITA data, we produced a first broadband 1-20 keV X-ray spectrum and estimated the pulsed fraction box 8 keV. With the addition of archival XMM-Newton observations, we traced the evolution of the spin period of SXP 1323 over the last five years and found that after 2016, the source switched to a linear spin-up with a rate of -29.9 s yr-1. The broadband X-ray spectrum is typical for accreting X-ray pulsars. It has a steep power-law index (Γ = -0.15) and an exponential cutoff energy of 5.1 keV. No significant difference between spectra obtained in states with and without pulsations were found.
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