NuSTAR observations of SWIFT J151857.0-572147: spectral analysis of the galactic X-ray transient source

Abstract

We study the spectral properties of the galactic X-ray transient source SWIFT J151857.0- 572147 using two NuSTAR observations from March 2024. The spectral analysis was performed using data from two onboard instruments, FPMA and FPMB of NuSTAR, in the broad energy range of 3_50 keV. To achieve the best fit, the spectral fitting required a combination of models: constant, power-law, multicolor disk-blackbody continuum, and Gaussian emission/absorption. Results show a hydrogen column density varying from 2.50 to 7.94×10²² cm⁻². The inner disk temperature of the source varied from 0.99 keV to 1.04 keV, and photon indices ranged from 1.74 to 4.08, indicating a transition from a low/hard to a high/soft state typical of black hole X-ray binaries.