Free‐Radical Polymerization in Reactive Supercritical Fluids

Beuermann, Sabine; Buback, Michael; Busch, Markus

doi:10.1002/9783527613687.ch16

Cited by 6 publications

(6 citation statements)

References 61 publications

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“…The narrow emission cores observed in CX1011 suggests a low-inclination system. However, we cannot exclude an origin for the emission in the irradiated donor star or hot spot instead of the disc as observed in the nova-like IX Vel (Beuermann & Thomas 1990). The optical spectrum of CX1011 resembles that of IX Vel except that in our spectrum we do not detect Hei λ4922 in emission and the Bowen blend appears stronger than the Heii λ4686 line.…”

Section: Cx772 = Cxogbs J1744050-263159mentioning

confidence: 91%

Identification of 23 accreting binaries in the Galactic Bulge Survey

Torres

Jonker

Britt

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We are undertaking a survey to characterize the X-ray sources found with the Chandra X-ray observatory in a strip of fields at −3 • < l < 3 • , b = +1.5 • and −3 • < l < 3 • , b = −1.5 • . This so-called Galactic Bulge Survey (GBS) targets X-ray emitting binaries in the bulge with the primary purpose of finding quiescent X-ray binaries. The aims of this survey are to quantify dynamically the mass of compact objects in these X-ray binaries in order to constrain the neutron star equation of state and to test black hole formation models. In addition, using the survey number counts of various sources we aim to test models for binary formation and evolution. Here, we present the identification of optical counterparts to twenty-three GBS X-ray sources. We report their accurate coordinates and medium resolution optical spectra acquired at the Very Large Telescope and Magellan. All sources are classified as accreting binaries according to their emission line characteristics. To distinguish accreting binaries from chromospherically active objects we develop and explain criteria based on Hα and Hei λλ5786, 6678 emission line properties available in the literature. The spectroscopic properties and photometric variability of all the objects are discussed and a classification of the source is given where possible. Among the twenty-three systems, at least nine of them show an accretion-dominated optical spectrum (CX28, CX63, CX70, CX128, CX142, CX207, CX522, CX794 CX1011) and another six show photospheric lines from a late-type donor star in addition to accretion disc emission (CX44, CX93, CX137, CX154, CX377 and CX1004) indicating that they are probably accreting binaries in quiescence or in a low accretion rate state. Two sources are confirmed to be eclipsing: CX207 and CX794. CX207 shows a broad asymmetric Hα profile blue-shifted by > 300 km s −1 . Such line profile characteristics are consistent with a magnetic (Polar) cataclysmic variable. CX794 is an eclipsing nova-like cataclysmic variable in the period gap. Time-resolved photometry and the large broadening of the Hα emission lines in CX446 (2100 km s −1 Full-Width at Half Maximum; FWHM) suggest that this is also an eclipsing or high-inclination accreting binary. Finally, the low-accretion rate source CX1004 shows a double-peaked Hα profile with a FWHM of 2100 km s −1 . This supports a high inclination or even eclipsing system. Whether the compact object is a white dwarf in an eclipsing cataclysmic variable or a black hole primary in a high-inclination low-mass X-ray binary remains to be established.

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Section: Cx772 = Cxogbs J1744050-263159mentioning

confidence: 91%

Identification of 23 accreting binaries in the Galactic Bulge Survey

Torres

Jonker

Britt

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…The higher-order Balmer series lines are too weak to overcome the intrinsic absorption from the disk atmosphere, and the wind fails to produce any observable emission at low and intermediate inclinations. This contrasts with the fact that emission lines are seen in the optical spectra of (for example) V3885 Sgr (Hartley et al 2005) and IX Vel (Beuermann & Thomas 1990, see also Fig. 1).…”

Section: Synthetic Spectramentioning

confidence: 79%

The Impact of Accretion Disc Winds on the Optical Spectra of Cataclysmic Variables

Matthews¹

2017

Disc Winds Matter

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Many high-state non-magnetic cataclysmic variables (CVs) exhibit blue-shifted absorption or P-Cygni profiles associated with ultraviolet (UV) resonance lines. These features imply the existence of powerful accretion disk winds in CVs. Here, we use our Monte Carlo ionization and radiative transfer code to investigate whether disk wind models that produce realistic UV line profiles are also likely to generate observationally significant recombination line and continuum emission in the optical waveband. We also test whether outflows may be responsible for the single-peaked emission line profiles often seen in high-state CVs and for the weakness of the Balmer absorption edge (relative to simple models of optically thick accretion disks). We find that a standard disk wind model that is successful in reproducing the UV spectra of CVs also leaves a noticeable imprint on the optical spectrum, particularly for systems viewed at high inclination. The strongest optical wind-formed recombination lines are Hα and He ii λ4686. We demonstrate that a higher-density outflow model produces all the expected H and He lines and produces a recombination continuum that can fill in the Balmer jump at high inclinations. This model displays reasonable verisimilitude with the optical spectrum of RW Trianguli. No single-peaked emission is seen, although we observe a narrowing of the double-peaked emission lines from the base of the wind. Finally, we show that even denser models can produce a single-peaked Hα line. On the basis of our results, we suggest that winds can modify, and perhaps even dominate, the line and continuum emission from CVs.

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“…Again, the location of the photocentre can be used to determine the size of the Roche lobe and hence the mass ratio Q. This approach assumes a certain relation between the velocities of the photocentre and the centre of mass and can be calculated with published irradiation models (Horne & Schneider 1989;Beuermann & Thomas 1990). In HU Aqr both methods yielded values of Q which were mutually exclusive and one had to compromise on an average value (see Fig.…”

Section: Basic Binary Parameters Derived From Doppler Mapsmentioning

confidence: 99%

Tomography of Polars

Schwope

Astrotomography

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We are reviewing the power of Doppler tomography for detailed investigations of polars (magnetic cataclysmic binaries without accretion disk). Using high-resolution spectroscopy in combination with tomography as analytic tool, the structure and extent of the accretion flows and accretion curtains in the binaries can be uncovered and the irradiated and non-irradiated parts of the mass-donating secondary stars can be made visible. In addition we show, how basic system parameters like the binary inclination and the mass ratio can be addressed by tomography.

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Free‐Radical Polymerization in Reactive Supercritical Fluids

Cited by 6 publications

References 61 publications

Identification of 23 accreting binaries in the Galactic Bulge Survey

Identification of 23 accreting binaries in the Galactic Bulge Survey

The Impact of Accretion Disc Winds on the Optical Spectra of Cataclysmic Variables

Tomography of Polars

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