2003/12/12 by P. Hakala, Pasi Hakala, Gavin Ramsay +1 · 3 citations
Physics and Astronomy · #Accretion (finance) #Accretion disc #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Eclipse #Intermediate polar #Light curve #Orbital period #Spectral line #Spectral slope #White dwarf #astro-ph
paper · pdf · doi:10.1051/0004-6361:20034059
published in Astronomy and Astrophysics 416(3), 1047-1055 (EDP Sciences) · 10 pages, 12 figures, accepted for publication in A&A
arxiv created 2003/12/12 · openalex publication_date 2004/03/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We revisit the XMM-Newton observations of the dwarf nova OY Car taken in July 2000 which occured shortly after an outburst. Ramsay et al. ([CITE]) found a prominent energy dependent modulation at a period of 2240 s: this modulation was only seen for ~1/3 of the observation duration. In our new analysis, we examine this time interval in greater detail. In addition to the 2240 s period we find evidence for other periods, the most prominent being near 3500 s. Both these modulations are most likely due to changes in photoelectric absorption over this period: this is supported by phase-resolved spectroscopy. This may indicate the presence of matter above the accretion disc or a presence of a magnetic accretion curtain. In this case the 2240 s period could represent a spin period of the white dwarf and the 3500 s period a beat period between the spin and orbital periods. We also model the B band and UV eclipse profiles and light curves using a new technique to map the spatial extent of the accretion disc. As a result we find that whilst the optical emission is dominated by both the emission close to the accretion disc boundary layer and the hot spot where the accretion stream hits the disc, the UV emission is mainly dominated by the inner disc/boundary layer only.