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Pye, Michael

doi:10.1057/9780230379411_16

Cited by 14 publications

(20 citation statements)

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“…It is a moderate‐redshift object (z=0.104) and relatively bright X‐ray source which has been observed over recent years by ASCA , ROSAT and BeppoSAX . 1H 0419−577 was also one of the brightest Seyfert galaxies detected in the extreme‐ultraviolet (EUV) by the ROSAT Wide Field Camera (Pye et al 1995) and EUVE (Marshall, Fruscione & Carone 1995). Optical spectra taken over the same period in 1996 as the ASCA and BeppoSAX X‐ray observations (Guainazzi et al 1998) show 1H 0419−577 to be a typical broad‐line Seyfert 1, in accordance with the classification by Brissenden (1989).…”

Section: Introductionmentioning

confidence: 99%

The highly variable X-ray spectrum of the luminous Seyfert 1 galaxy 1H 0419-577

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Pounds

Reeves

et al. 2002

Monthly Notices of the Royal Astronomical Society

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An XMM‐Newton observation of the luminous Seyfert 1 galaxy 1H 0419−577 is presented. We find that the spectrum is well fitted by a power law of canonical slope (Γ∼1.9) and three blackbody components (to model the strong soft excess). The XMM‐Newton data are compared and contrasted with observations by ROSAT in 1992 and by ASCA and BeppoSAX in 1996. We find that the overall X‐ray spectrum has changed substantially over the period, and suggest that the changes are driven by the soft X‐ray component. When bright, as in our XMM‐Newton observation, it appears that the enhanced soft flux cools the Comptonizing corona, causing the 2–10 keV power law to assume a ‘typical’ slope, in contrast to the unusually hard (‘photon‐starved’) spectra observed by ASCA and BeppoSAX 4 years earlier.

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Section: Introductionmentioning

confidence: 99%

The highly variable X-ray spectrum of the luminous Seyfert 1 galaxy 1H 0419-577

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Pounds

Reeves

et al. 2002

Monthly Notices of the Royal Astronomical Society

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“…Indeed, 20 out of a total 29 systems (67%) are parts of hierarchical multiple systems in Figure 1, indicated with filled squares. The difference in L X distribution between single and binary dK dwarfs with orbital periods longer than 1 yr in the Hyades is very pronounced, reaching almost an order of magnitude (Pye et al 1994). Half of the high-fidelity Hyades members with log L X / log L Bol > −4.8 reside in visual binaries with separations precluding any tidal interactions between the components (Makarov 2000).…”

Section: Introductionmentioning

confidence: 99%

The Origin of Bright X-Ray Sources in Multiple Stars

Макаров

Eggleton

2009

ApJ

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Luminous X-ray stars are very often found in visual double or multiple stars. Binaries with periods of a few days possess the highest degree of coronal X-ray activity among regular, non-relativistic stars because of their fast, tidally driven rotation. But the orbital periods in visual double stars are too large for any direct interaction between the companions to take place. We suggest that most of the strongest X-ray components in resolved binaries are yetundiscovered short-period binaries, and that a few are merged remnants of such binaries. The omnipresence of shortperiod active stars, e.g., of BY-Dra-type binaries, in multiple systems is explained via the dynamical evolution of triple stars with large mutual inclinations. The dynamical perturbation on the inner pair pumps up the eccentricity in a cyclic manner, a phenomenon known as Kozai cycling. At times of close periapsis, tidal friction reduces the angular momentum of the binary, causing it to shrink. When the orbital period of the inner pair drops to a few days, fast surface rotation of the companions is driven by tidal forces, boosting activity by a few orders of magnitude. If the period drops still further, a merger may take place leaving a rapidly rotating active dwarf with only a distant companion.

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“…A new EUV/soft X‐ray source (2RE J1440+750, Pye et al 1995; EUVE J1439+75.0, Bowyer et al 1996) was identified with an isolated hot hydrogen‐rich white dwarf (Vennes et al 1997). A single spectrum of the optical counterpart of EUVE J1439+75.0 (Fig.…”

Section: Observationsmentioning

confidence: 99%

The new magnetic / non-magnetic double degenerate system EUVE J1439+75.0

Vennes

Ferrario

Wickramasinghe

1999

Monthly Notices of the Royal Astronomical Society

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Optical spectroscopy of the extreme ultraviolet source EUVE J1439 + 75.0 revealed a new unresolved double degenerate system. The system is composed of two hot white dwarfs (Teff≥ 20, 000 K), one magnetic (∼ 10 MG) and the other apparently non‐magnetic. Surface gravity measurements imply masses of ∼ 1.0 and ∼ 0.9 M⊙ for the magnetic and non‐magnetic white dwarfs, respectively. Proposed radial velocity and spectro‐polarimetric studies may help uncover evidence of past interactions and clarify the evolutionary status of the pair.

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Cited by 14 publications

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The highly variable X-ray spectrum of the luminous Seyfert 1 galaxy 1H 0419-577

The highly variable X-ray spectrum of the luminous Seyfert 1 galaxy 1H 0419-577

The Origin of Bright X-Ray Sources in Multiple Stars

The new magnetic / non-magnetic double degenerate system EUVE J1439+75.0

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