Polars in the ROSAT Era I: Overview

Beuermann, K.; Burwitz, V.; Reinsch, K.; Schwope, A. D.; Thomas, H. C.

doi:10.1007/978-94-011-0335-0_111

Cited by 88 publications

(144 citation statements)

References 25 publications

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“…It has a relatively bright optical counterpart of 12.5 mag. This star was studied photometrically and spectroscopically by Beuermann et al (1995), who derived a photometric and spectroscopic period of about 0.66 days. Greiner & Wenzel (1995), from observations taken in the interval 1955-1993, found a period of 0.6604565( ± 15) days, while Will & Barwig (1996) derived for the interval September 1992 to October 1995 a period of 0.6604721 ( ± 72) days.…”

Section: The Galactic Cbss Sources Rx J00198+2156 and Rx J09257-4758mentioning

confidence: 99%

Luminous Supersoft X-Ray Sources

Kahabka

Heuvel

1997

Annu. Rev. Astron. Astrophys.

328

262

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Luminous supersoft X-ray sources were discovered with the Einstein observatory and have been established as an important new class of X-ray binaries on the basis of observations with the Roentgen Satellite (ROSAT). They have extremely soft spectra (equivalent blackbody temperatures of ∼15-80 eV) and are highly luminous (bolometric luminosities of 10 36 -10 38 erg s −1 ). Correcting for the heavy extinction of soft X rays by interstellar neutral hydrogen, their numbers in the disks of ordinary spiral galaxies like our own and M31 are estimated to be of the order of 10 3 . Their observed characteristics are consistent with those of white dwarfs, which are steadily or cyclically burning hydrogen-rich matter accreted onto the surface at a rate of order 10 −7 M year −1 . The required high accretion rates can be supplied by mass transfer on a thermal time scale (10 6 -10 7 years) from close companion stars that are more massive than the white dwarf accretor, typically 1.3-2.5 M . Steady burning can also occur in a post-nova stage, but for shorter time scales, and it has been observed in a few classical novae and symbiotic novae. A few supersoft sources have been found to be recurrent transients. They are possibly connected with very massive white dwarfs accreting at high rates. Luminous supersoft sources may make a considerable contribution to the Type Ia supernova rate in spiral and irregular galaxies.

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Section: The Galactic Cbss Sources Rx J00198+2156 and Rx J09257-4758mentioning

confidence: 99%

Luminous Supersoft X-Ray Sources

Kahabka

Heuvel

1997

Annu. Rev. Astron. Astrophys.

328

262

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“…Two are recently exploded novae, two are symbiotic novae, and one is unclassified. Thus, there are only two good NBWD candidates in the Galaxy: RX J0925.7-4758 (Motch, Hasinger, & Pietsch 1994) and RX J0019.8+2156 (hereafter RXJ0019; Beuermann et al 1995). Since RX J0925.7-4758 is obscured by the Vela Sheet molecular cloud, and its intrinsic optical spectrum is heavily reddened (Motch, Hasinger, & Pietsch 1994;Grabelsky et al 1987), RXJ0019 remains as the one prime galactic NBWD candidate for detailed optical study.…”

Section: Introductionmentioning

confidence: 99%

“…Since RX J0925.7-4758 is obscured by the Vela Sheet molecular cloud, and its intrinsic optical spectrum is heavily reddened (Motch, Hasinger, & Pietsch 1994;Grabelsky et al 1987), RXJ0019 remains as the one prime galactic NBWD candidate for detailed optical study. Beuermann et al (1995) discovered RXJ0019 as part of the ROSAT all-sky survey in 1990 December. They subsequently initiated a battery of short ROSAT PSPC, ROSAT HRI, IUE, and optical observations in 1992-93 (Beuermann et al 1995).…”

Section: Introductionmentioning

confidence: 99%

“…Beuermann et al (1995) discovered RXJ0019 as part of the ROSAT all-sky survey in 1990 December. They subsequently initiated a battery of short ROSAT PSPC, ROSAT HRI, IUE, and optical observations in 1992-93 (Beuermann et al 1995). The following is a brief summary of their results.…”

Section: Introductionmentioning

confidence: 99%

“…In this work we present our spectroscopic observations of RXJ0019. The radial velocity work of Beuermann et al (1995), was completed in four days. In contrast, our observations span ∼ 2.5 yr and allow us to probe the spectral features and the stability of radial velocity measurements over a much longer baseline.…”

Section: Introductionmentioning

confidence: 99%

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Bipolar Jets and Orbital Dynamics of the Supersoft X‐Ray Source RX J0019.8+2156

Becker

Remillard

Rappaport

et al. 1998

ApJ

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Between 1994 July and 1997 February we monitored the optical spectrum of RX J0019.8]2156. This supersoft X-ray source is one of only two accreting white dwarfs in the Galaxy that are thought to be burning hydrogen on their surface as a consequence of a high rate of mass transfer from a binary companion. Accurate orbital ephemerides are derived from radial velocity measurements for the white dwarf, which are obtained from strong He II emission lines with a stable velocity semiamplitude of K \ 71.2^3.6 km s~1. We report the discovery of transient, low-velocity, bipolar jets. These jets are represented by redshifted-blueshifted pairs of emission lines from H and He II with an outÑow velocity of v cos (i) D 815 km s~1, where i is the binary inclination angle. When present, the jet lines seen in Ha also exhibit an orbital modulation of 71 km s~1, which strengthens the interpretation that this is the orbital velocity of the white dwarf and also indicates that the jets are oriented nearly perpendicular to the orbital plane. On most occasions, the H emission line proÐles are further altered by P Cygni absorption e †ects, and the strength of this absorption is also dependent on binary phase. We show that the jets and the P Cygni features have very di †erent temporal characteristics and binary phase dependence ; thus, we conclude that the outÑowing material and the absorbing wind must have essentially di †erent geometries. Finally, the measured mass function is combined with binary evolution models to suggest a limit on the inclination angle, i \ 40¡. A particular model invoked to explain a high rate of mass transfer requires 16¡ \ i \ 25¡. However, at such small inclination it is difficult to explain the large amplitude of the orbital light curve (D0.5 mag). Alternatively, the results could signify substantial vertical structure in the accretions disks of supersoft X-ray sources. By contrast, a simple model Ðt to the jet outÑow lines indicates an orbital inclination angle of 35¡ \ i \ 60¡.

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X-Ray Transient Galaxies and AGN

Grupe

Eso Astrophysics Symposia

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X-ray transience is the most extreme form of variability observed in AGN or normal in-active galaxies. While factors of 2-3 on timescales of days to years are quite commen among AGN, X-ray transients appear only once and vanish from the X-ray sky years later. The ROSAT All-Sky Survey was the tool to discover these sources. X-ray transience in AGN or galaxies can be caused by dramatic changes in the accretion rate of the central black hole or by changes of the properties of the accretion disk.

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Polars in the ROSAT Era I: Overview

Cited by 88 publications

References 25 publications

Luminous Supersoft X-Ray Sources

Luminous Supersoft X-Ray Sources

Bipolar Jets and Orbital Dynamics of the Supersoft X‐Ray Source RX J0019.8+2156

X-Ray Transient Galaxies and AGN

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