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arXiv · 2110.06642

Broad-band analysis of X-ray pulsar 2S 1845$-$024

Armin Nabizadeh·Sergey S. Tsygankov·Sergey V. Molkov·Dmitri I. Karasev·Long Ji·Alexander A. Lutovinov·Juri Poutanen
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Abstract

We present results of detailed investigation of the poorly studied X-ray pulsar 2S 1845$-$024 based on the data obtained with $NuSTAR$ observatory during the type I outburst in 2017. Neither pulse phase-averaged, nor phase-resolved spectra of the source show evidence for a cyclotron absorption feature. We also used the data obtained from other X-ray observatories ($Swift$, $XMM-Newton$ and $Chandra$) to study the spectral properties as a function of orbital phase. The analysis revealed a high hydrogen column density for the source reaching $\sim$10$^{24}$ cm$^{-2}$ around the periastron. Using high-quality $Chandra$ data we were able to obtain an accurate localization of 2S 1845$-$024 at R.A. = 18$^{h}$48$^{m}$16$^{s}$.8 and Dec. = $-$2$^{\circ}$25'25".1 (J2000) that allowed us to use infrared (IR) data to roughly classify the optical counterpart of the source as an OB supergiant at the distance of $\gtrsim$15 kpc.

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Armin Nabizadeh, Sergey S. Tsygankov, Sergey V. Molkov, Dmitri I. Karasev, Long Ji, Alexander A. Lutovinov, Juri Poutanen. 2021-10-13. Broad-band analysis of X-ray pulsar 2S 1845$-$024. https://doi.org/10.1051/0004-6361%2F202141608

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