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arXiv · 2101.07030

X-ray pulsar XTE J1858+034: discovery of the cyclotron line and the revised optical identification

Sergey S. Tsygankov·Alexander A. Lutovinov·Sergey V. Molkov·Anlaug A. Djupvik·Dmitri I. Karasev·Victor Doroshenko·Alexander A. Mushtukov·Christian Malacaria·Peter Kretschmar·Juri Poutanen
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Abstract

We present results of a detailed investigation of the poorly studied X-ray pulsar XTE J1858+034 based on the data obtained with the NuSTAR observatory during the outburst of the source in 2019. The spectral analysis resulted in the discovery of a cyclotron absorption feature in the source spectrum at ~48 keV both in the pulse phase averaged and resolved spectra. Accurate X-ray localization of the source using the NuSTAR and Chandra observatories allowed us to accurately determine the position of the X-ray source and identify the optical companion of the pulsar. The analysis of the counterpart properties suggested that the system is likely a symbiotic binary hosting an X-ray pulsar and a late type companion star of K-M classes rather than Be X-ray binary as previously suggested.

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Sergey S. Tsygankov, Alexander A. Lutovinov, Sergey V. Molkov, Anlaug A. Djupvik, Dmitri I. Karasev, Victor Doroshenko, Alexander A. Mushtukov, Christian Malacaria, Peter Kretschmar, Juri Poutanen. 2021-01-18. X-ray pulsar XTE J1858+034: discovery of the cyclotron line and the revised optical identification. https://doi.org/10.3847/1538-4357%2Fabddbd

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