Refereed journal article or data article (A1)

On the nature of the X-ray pulsar XTE J1859+083 and its broad-band properties




List of Authors: Salganik Alexander, Tsygankov Sergey S., Djupvik Anlaug A., Karasev Dmitri I., Lutovinov Alexander A., Buckley David A. H., Gromadzki Mariusz, Poutanen Juri

Publisher: OXFORD UNIV PRESS

Publication year: 2022

Journal: Monthly Notices of the Royal Astronomical Society

Journal acronym: MON NOT R ASTRON SOC

Volume number: 509

Issue number: 4

Number of pages: 9

ISSN: 0035-8711

eISSN: 1365-2966

DOI: http://dx.doi.org/10.1093/mnras/stab3362

URL: https://academic.oup.com/mnras/article/509/4/5955/6440179

Self-archived copy’s web address: https://arxiv.org/abs/2111.08997v1


Abstract

This work is devoted to the study of the broad-band 0.8-79 keV spectral and timing properties of the poorly studied X-ray pulsar XTE J1859 +083 during its 2015 outburst based on the data from the NuSTAR and Swift observatories. We show that the source pulse profile has complex shape that depends on the energy band. Pulse fraction of XTE J1859+083 has constant value around 35 per cent in the broad energy band, this behaviour is atypical for X-ray pulsars. At the same time its energy spectrum is typical of this class of objects and has a power-law shape with an exponential cutoff at high energies. No cyclotron absorption line was discovered in the source spectrum. On the basis of indirect method and the absence of a cyclotron line, an estimation was made for the magnetic field strength as less than 5 x10(11) G or belonging to the interval from 5 x10(12) to 2.0(-1.2)(+0.9) x10(13) G. Data from the NOT and SALT telescopes as well as optical and IR sky surveys allowed us also to study the nature of its optical companion. We have proposed and studied new possible candidates for the optical companion of XTE J1859+083 and the most likely candidate was identified. The results of the optical and IR photometry and spectroscopy of these possible companions showed that the system is a Be X-ray binary, showing Br gamma, He I, and strong H alpha spectral lines.


Last updated on 2022-05-12 at 15:10