Identification of 1RXS J165424.6-433758 as a Polar Cataclysmic Variable

B. O’Connor, J. Brink, D. A.H. Buckley, K. Mukai, C. Kouveliotou, E. Göğüş, S. B. Potter, P. Woudt, A. Lien, A. Levan, O. Kargaltsev, M. G. Baring, E. Bellm, S. B. Cenko, P. A. Evans, J. Granot, C. Hailey, F. Harrison, D. Hartmann, A. J. van der HorstD. Huppenkothen, L. Kaper, J. A. Kennea, P. O. Slane, D. Stern, E. Troja, R. A.M.J. Wijers, G. Younes

Research output: Contribution to journalArticlepeer-review


We present the results of our X-ray, ultraviolet, and optical follow-up campaigns of 1RXS J165424.6-433758, an X-ray source detected with the Swift Deep Galactic Plane Survey. The source X-ray spectrum (Swift and NuSTAR) is described by thermal bremsstrahlung radiation with a temperature of kT = 10.1 ± 1.2 keV, yielding an X-ray (0.3-10 keV8) luminosity L X = (6.5 ± 0.8) × 1031 erg s−1 at a Gaia distance of 460 pc. Spectroscopy with the Southern African Large Telescope revealed a flat continuum dominated by emission features, demonstrating an inverse Balmer decrement, the λ4640 Bowen blend, almost a dozen He i lines, and He ii λ4541, λ4686, and λ5411. Our high-speed photometry demonstrates a preponderance of flickering and flaring episodes, and revealed the orbital period of the system, P orb = 2.87 hr, which fell well within the cataclysmic variable (CV) period gap between 2 and 3 hr. These features classify 1RXS J165424.6-433758 as a nearby polar magnetic CV.

Original languageEnglish
Article number89
JournalAstrophysical Journal
Issue number2
StatePublished - 1 Nov 2023

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© 2023. The Author(s). Published by the American Astronomical Society.


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