Confirmation of 1RXS J165443.5-191620 as an intermediate polar and its orbital and spin periods

S. Scaringi, S. Connolly, J. Patterson, J. R. Thorstensen, H. Uthas, C. Knigge, L. Vican, B. Monard, R. Rea, T. Krajci, S. Lowther, G. Myers, G. Bolt, A. Dieball, P. J. Groot

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Aims. We investigate the physical nature of the X-ray emitting source 1RXS J165443.5-191620 through optical photometry and time-resolved spectroscopy. Methods. Optical photometry is obtained from a variety of telescopes all over the world spanning ≈ 27 days. Additionally, time-resolved spectroscopy is obtained from the MDM observatory. Results. The optical photometry clearly displays modulations consistent with those observed in magnetic cataclysmic variables: a low-frequency signal interpreted as the orbital period, a high-frequency signal interpreted as the white dwarf spin period, and an orbital sideband modulation. Our findings and interpretations are further confirmed through optical, time-resolved spectroscopy that displays Hα radial velocity shifts modulated on the binary orbital period. Conclusions. We confirm that 1RXS J165443.5-191620 is an intermediate polar with a spin period of 546 s and an orbital period of 3.7 h. In particular, 1RXS J165443.5-191620 is part of a growing subset of intermediate polars that display hard X-ray emission above 15 keV, white dwarf spin periods below 30 min, and spin-to-orbital ratios below 0.1.

Original languageEnglish
Article numberA6
JournalAstronomy and Astrophysics
StatePublished - 2011


  • X-rays: binaries
  • binaries: close
  • stars: individual: 1RXS J165443.5-191620
  • stars: individual: IGR J16547-1916
  • white dwarfs


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