Swift Deep Galactic Plane Survey Classification of Swift J170800$-$402551.8 as a Candidate Intermediate Polar Cataclysmic Variable

B. O'Connor; E. Gogus; J. Hare; K. Mukai; D. Huppenkothen; J. Brink; D. A. H. Buckley; A. Levan; M. G. Baring; R. Stewart; C. Kouveliotou; P. Woudt; E. Bellm; S. B. Cenko; P. A. Evans; J. Granot; C. Hailey; F. Harrison; D. Hartmann; A. J. van der Horst; L. Kaper; J. A. Kennea; S. B. Potter; P. O. Slane; D. Stern; R. A. M. J. Wijers; G. Younes

arXiv · 2307.13959

Swift Deep Galactic Plane Survey Classification of Swift J170800$-$402551.8 as a Candidate Intermediate Polar Cataclysmic Variable

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Abstract

Here, we present the results of our multi-wavelength campaign aimed at classifying \textit{Swift} J170800$-$402551.8 as part of the \textit{Swift} Deep Galactic Plane Survey (DGPS). We utilized Target of Opportunity (ToO) observations with \textit{Swift}, \textit{NICER}, \textit{XMM-Newton}, \textit{NuSTAR}, and the Southern African Large Telescope (SALT), as well as multi-wavelength archival observations from \textit{Gaia}, VPHAS, and VVV. The source displays a periodicity of 784 s in our \textit{XMM-Newton} observation. The X-ray spectrum (\textit{XMM-Newton} and \textit{NuSTAR}) can be described by thermal bremsstrahlung radiation with a temperature of $kT$\,$\approx$\,$30$ keV. The phase-folded X-ray lightcurve displays a double-peaked, energy-dependent pulse-profile. We used \textit{Chandra} to precisely localize the source, allowing us to identify and study the multi-wavelength counterpart. Spectroscopy with SALT identified a Balmer H$\alpha$ line, and potential HeI lines, from the optical counterpart. The faintness of the counterpart ($r$\,$\approx$\,$21$ AB mag) favors a low-mass donor star. Based on these criteria, we classify \textit{Swift} J170800$-$402551.8 as a candidate intermediate polar cataclysmic variable, where the spin period of the white dwarf is 784 s.

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B. O'Connor, E. Gogus, J. Hare, K. Mukai, D. Huppenkothen, J. Brink, D. A. H. Buckley, A. Levan, M. G. Baring, R. Stewart, C. Kouveliotou, P. Woudt, E. Bellm, S. B. Cenko, P. A. Evans, J. Granot, C. Hailey, F. Harrison, D. Hartmann, A. J. van der Horst, L. Kaper, J. A. Kennea, S. B. Potter, P. O. Slane, D. Stern, R. A. M. J. Wijers, G. Younes. 2023-07-26. Swift Deep Galactic Plane Survey Classification of Swift J170800$-$402551.8 as a Candidate Intermediate Polar Cataclysmic Variable. https://arxiv.org/abs/2307.13959

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