Discovery of periodic eclipses in the X-ray pulsar 1H 0253 + 193

Kamata, Yuichi; Tawara, Yuzuru; Koyama, K.

doi:10.1086/186155

Cited by 17 publications

(25 citation statements)

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“…However, the discovery of X‐ray pulsations with a 206‐s period (Takano et al 1989) suggested that the X‐rays originated from accretion onto a strongly magnetized, rotating compact object. Patterson & Halpern (1990) noted that the X‐ray properties of XY Ari strongly resemble those of an intermediate polar (IP) and the binary nature of the system was confirmed with the discovery of X‐ray eclipses recurring with a 6.06‐h orbital period (Kamata, Tawara & Koyama 1991). XY Ari is the only intermediate polar to exhibit deep X‐ray eclipses.…”

Section: Introductionmentioning

confidence: 90%

K-band spectroscopy of the intermediate polar XY Ari

Littlefair

Dhillon

Marsh

2001

Monthly Notices of the Royal Astronomical Society

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We present the K-band infrared spectrum of the intermediate polar XY Ari. The spectrum confirms the cataclysmic binary nature of XY Ari, showing emission lines of HeI (2.0587 microns) and the Brackett and Paschen series of HI. The broad nature of these lines suggest an origin in an accretion disc. The spectrum is strongly reddened by absorption within the molecular cloud Lynds 1457 and shows prominent absorption features from the secondary star, from which we determine a spectral type for the secondary of M0V. The secondary contributes 80 +/- 6% of the K-band light. We derive a visual extinction to XY Ari of Av = 11.5 +/- 0.3 and a distance of d=270 +/- 100 pc, placing XY Ari behind the molecular cloud.Comment: 5 pages, 2 figures, to appear in Monthly Notices, accepte

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Section: Introductionmentioning

confidence: 90%

K-band spectroscopy of the intermediate polar XY Ari

Littlefair

Dhillon

Marsh

2001

Monthly Notices of the Royal Astronomical Society

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“…Subsequent short Ginga observations in July 1987 and January 1989 discovered a coherent X-ray pulsation with a period of 206 s and a double-peaked profile (Takano et al 1989;Koyama et al 1991), suggesting its identification as an IP (Patterson & Halpern 1990). Further, longer observations with the same satellite in August 1989 discovered eclipses with a period of 6.06 h (Kamata et al 1991), so establishing the orbital period of the system and making it the first (and so far only) IP to exhibit deep X-ray eclipses.…”

Section: The History Of Xy Arimentioning

confidence: 99%

A precessing accretion disc in the intermediate polar XY Arietis?

Norton¹,

Mukai²

2007

A&A

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Context. XY Ari is the only intermediate polar to show deep X-ray eclipses of its white dwarf. Previously published observations with Ginga and Chandra have also revealed a broad X-ray orbital modulation, roughly antiphased with the eclipse, and presumed to be due to absorption in an extended structure near the edge of an accretion disc. The X-ray pulse profile is generally seen to be double-peaked, although a single-peaked pulse was seen by RXTE during an outburst in 1996. Aims. We intended to investigate the cause of the broad orbital modulation in XY Ari to better understand the accretion flow in this system and other intermediate polars.Methods. We observed XY Ari with RXTE and analysed previously unpublished archival observations of the system made with ASCA and XMM-Newton. These observations comprise six separate visits and span about ten years.Results. The various X-ray observations show that the broad orbital modulation varies in phase and significance, then ultimately disappears entirely in the last few years. In addition, the X-ray pulse profile shows variations in depth and shape, and in the recent RXTE observations displays no evidence for changes in hardness ratio. Conclusions. The observed changes indicates that both the pulse profile and the orbital modulation are solely due to geometrical effects at the time of the RXTE observations, rather than phase-dependent variations in photoelectric absorption as seen previously. We suggest that this is evidence for a precessing, tilted accretion disc in this system. The precession of the disc moves structures out of our line of sight both at its outer edge (changing the orbital modulation) and at its inner edge where the accretion curtains are anchored (changing the pulse profile).

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“…I therefore proceed with the range 80 • < i <84 • . The length of the X-ray eclipse (2050 s; Kamata et al 1991;Allan et al 1996) then fixes the mass ratio to 0.48 < q <0.68, using figure 2 of Horne (1985). For these values of q and i the angle of the secondary star limb at the white dwarf (θ in Fig.…”

Section: The Location Of the Accretion Regionsmentioning

confidence: 99%

The size of the accretion region in intermediate polars: eclipses of XY Arietis observed with RXTE

Hellier¹

1997

Monthly Notices of the Royal Astronomical Society

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RXTE observed 20 eclipse egresses of the intermediate polar XY Ari in order to study the size and structure of the X-ray emitting accretion regions. The spin-phase averaged egress lasts 26 s, implying a white dwarf radius of 4.3-7.0 ×10 8 cm. The individual egresses occur later in orbital phase with later spin phase, as expected if the white dwarf spins in the same sense as the orbital motion. The eclipse times trace out the motion of the upper pole across the white dwarf face; then, when the upper pole disappears over the white dwarf limb and the lower pole appears, they trace the motion of the lower pole across the face.Aligning all the egresses shows that the majority of the X-ray flux emerges in < 2 s, implying accretion regions with area, f , < 0.002 as a fraction of the white dwarf surface. Using only the spin-phase to align the egresses, however, gives a longer (∼ 5 s) time for the emergence of the majority of the flux, implying that the accretion regions wander over an area of f < 0.01. There is also evidence that a minority of the flux emerges from a much larger area, or that we see accretion regions at both poles simultaneously at some spin phases.

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Discovery of periodic eclipses in the X-ray pulsar 1H 0253 + 193

Cited by 17 publications

References 0 publications

K-band spectroscopy of the intermediate polar XY Ari

K-band spectroscopy of the intermediate polar XY Ari

A precessing accretion disc in the intermediate polar XY Arietis?

The size of the accretion region in intermediate polars: eclipses of XY Arietis observed with RXTE

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