Simultaneous optical polarimetry and X-ray data of the near-synchronous polar RX J2115-5840

Ramsay, Gavin; Potter, S.; Cropper, Mark; Buckley, D.; Harrop-Allin, M. K.

doi:10.1046/j.1365-8711.2000.03507.x

Cited by 28 publications

(35 citation statements)

References 21 publications

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“…This variability is best shown in the Ginga data which was taken over 3 days and showed a periodic modulation in the first half which disappeared in the second half and was thereafter dominated by strong flaring. This is consistent with X‐ray observations of one other asynchronous polar RX J2115–58 which showed highly variable light curves (Ramsay et al 2000). This variability was interpreted as the accretion flow rotating around the magnetic field of the white dwarf and at certain instances the flow accretes on to the opposite hemisphere of the white dwarf resulting in a different shaped light curve.…”

Section: Introductionsupporting

confidence: 91%

XMM-Newton observations of the asynchronous polar BY Cam

Ramsay

Cropper

2002

Monthly Notices of the Royal Astronomical Society

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We report observations of the asynchronous polar BY Cam made using XMM-Newton. We find evidence for two accretion regions which have significantly different spectra. In both regions we find evidence for hard X-ray emission from the post-shock flow while we observe a distinct soft X-ray blackbody component in only one. We detect two emission lines in the RGS detectors which we attribute to Nitrogen NVI and NVII: the first time that Nitrogen lines have been detected in an X-ray spectrum of a cataclysmic variable. In the time interval where we observe short timescale variability we find the hard X-ray light curve is correlated with the softest energies in the sense that the hard X-rays trail the soft X-rays and are anti-correlated. We suggest that there are a small number of dense blobs of material which impact the white dwarf without forming a shock and release an amount of optically thick material which obscures hard X-rays for a short duration.

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Section: Introductionsupporting

confidence: 91%

XMM-Newton observations of the asynchronous polar BY Cam

Ramsay

Cropper

2002

Monthly Notices of the Royal Astronomical Society

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“…It was first discovered in V1500 Cyg in 1988 in the form of ~7 day variations in the average brightness [7], which can be in the shape of a one or two hump wave [8]. Ramsay et al [9] found variations in the circular polarization of RX J2115-5840 with a period of 6.3 days, while Friedrich et al [10] discovered a modulation in the x-ray light curves with the phase of a beat period of 49.5 days. The most vivid manifestation of this period in BY Cam was found during the international "Noah project" [11]: twice the synodic cycle (14.…”

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confidence: 99%

Magnetic field structure and accretion regimes of the asynchronous polar by Cam

Павленко

2006

Astrophysics

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Series of photometric CCD observations of the asynchronous polar BY Cam in a low accretion state (R = 14 m -16 m ) were made on the K-380 telescope at the Crimean Astrophysical Observatory (CrAO) over 100 hours in the course of 31 nights during [2004][2005]. A period of P 1 = 0.137120 ± 0.000002 days was found for the variations in the brightness, along with less significant periods of P 2 = 0.139759 ± 0.000003 and P 3 = 0.138428 ± 0.000002 days, where P 2 and P 3 are obviously the orbital and rotation periods, while the dominant period P 1 is the sideband period. A modulation in the brightness and an amplitude of 0.137 days in the oscillations at the orbital-rotational beat period (synodic cycle) of 14.568 ± 0.003 day are found for the first time. The profile of the modulation period is four humped. This indicates that the magnetic field has a quadrupole component, which shows up well during the low brightness state. Accretion takes place simultaneously into two or three accretion zones, but at different rates. The times of the times of maxima for the main accretion zone vary with the phase of the beat period. Three types of variation of this sort are distinguished: linear, discontinuous, and chaotic, which indicate changes in the accretion regimes. At synodic phases 0.25 and 0.78 the bulk of the stream switches by 180°, and at phase 0.55, by ~75°. At phases of 0.25-0.55 and 0.55-0.78, the O-C shift with a period of 0.1384 days, which can be explained by a retrograde shift of the main accretion zone relative to the magnetic pole and/or a change in the angle between the field lines and the surface of the white dwarf owing to the asynchronous rotation. For phases of 0.78-1.25 the motion of the accretion zone is quite chaotic. It is found that synchronization of the components occurs at a rate of less than dP rot /P rot~1 0 -9 day/day.

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“…There are four known nearly synchronous Polars: V1500 Cyg (e.g., Schmidt et al 1995), BY Cam (e.g., Mason et al 1998), V1432 Aql (e.g., Geckeler & Staubert 1997), RX J2115À5840 (Ramsay et al 2000), and one candidate, V4633 Sgr (Lipkin et al 2001). Warner (1995) explained that as the primary of the binary system rotates asynchronously, the accretion flow is more variable than for a phase-locked Polar.…”

Section: A Nearly Synchronous Polar?mentioning

confidence: 99%

Detection of Orbital and Superhump Periods in Nova V2574 Ophiuchi (2004)

Kang

Retter

Liu³

et al. 2006

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We present the results of 37 nights of CCD unfiltered photometry of nova V2574 Oph (2004) show variability on a similar timescale, but no coherent periodicity was found. We suggest that the longer periodicity is the orbital period of the underlying binary system and that the shorter period represents a negative superhump. The 3.40 hr period is about 4% shorter than the orbital period and obeys the relation between superhump period deficit and binary period. The detection of superhumps in the light curve is evidence of the presence of a precessing accretion disk in this binary system shortly after the nova outburst. From the maximum magnitude-rate of decline relation, we estimate the decay rate t 2 ¼ 17 AE 4 days and a maximum absolute visual magnitude of M V max ¼ 7:7 AE 1:7 mag.

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Simultaneous optical polarimetry and X-ray data of the near-synchronous polar RX J2115-5840

Cited by 28 publications

References 21 publications

XMM-Newton observations of the asynchronous polar BY Cam

XMM-Newton observations of the asynchronous polar BY Cam

Magnetic field structure and accretion regimes of the asynchronous polar by Cam

Detection of Orbital and Superhump Periods in Nova V2574 Ophiuchi (2004)

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