Hostname: page-component-848d4c4894-xm8r8 Total loading time: 0 Render date: 2024-06-26T21:29:05.352Z Has data issue: false hasContentIssue false
  • English
  • Français

Time-Dependent X-Ray Observations of Wolf-Rayet Binaries with 0-Type and with Suspected Compact Companions

Published online by Cambridge University Press:  14 August 2015

A.F.J. Moffat ,
C. Firmani ,
I.S. McLean  and
W. Seggewiss
A.F.J. Moffat
Affiliation:
Département de physique, Université de Montréal
C. Firmani
Affiliation:
Instituto de Astronomia, Universidad Nac. Aut. de Mexico
I.S. McLean
Affiliation:
Royal Observatory, Edinburgh
W. Seggewiss
Affiliation:
Observatorium Hoher List der Universität Bonn

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Each of four WR binaries has been observed in the 0.1 −5 keV range on four consecutive days for a total of ∼ 104 sec with the IPC on the Einstein Observatory. One of the stars is the well-known WN5 + 06 binary V444 Cyg; the other three have suspected compact companions; all have periods close to four days.

Neither HD 197406 (WN7) nor HD 96548 (WN8) was detected; hence Lx (0.5–3.0 keV) ≲ 1032 erg s−1, which is on the low side, even for 0-stars. EZ CMa (WN5) and V444 Cyg are moderately strong, variable X-ray sources with Lx (0.5–3.0 keV) ≃ 1033 erg s−1, kT ≃ 0.5 keV and NH ≃ 1022 cm−2. These values suggest that the X-ray flux arises in the outer part of the wind. The variable component may be produced by collision of two winds.

There is no evidence of harder X-rays coming from accretion onto a compact star. Nevertheless, the presence of a collapsar is not excluded at hv ≲ 5 keV, where absorption in the WR wind would likely reduce the X-ray flux to a level which is masked by the flux coming from the hot stellar wind.

Type
SESSION 8 — X-RAY DATA — MISCELLANEOUS TOPICS — GENERAL DISCUSSION
Information
Symposium - International Astronomical Union , Volume 99: Wolf-Rayet Stars: Observations, Physics, Evolution , 1982 , pp. 577 - 581
Copyright
Copyright © Reidel 1982 

References

Bracher, K. 1979, PASP 91, 827.Google Scholar
Cassinelli, J.P., Sanders, W.T., van der Hucht, K.A. 1982, this symposium.Google Scholar
Cherepashchuk, A.M. 1976, Sov. Astron. Lett. 2, 138.Google Scholar
Chlebowski, T., Seward, F.D. 1981, BAAS 13, 512.Google Scholar
Firmani, C., Koenigsberger, G., Bisiacchi, G.F., Moffat, A.F.J., Isserstedt, J. 1980, Ap. J. 239, 607.Google Scholar
Hidayat, B., Supelli, K., van der Hucht, K.A. 1981, preprint.Google Scholar
Kron, G.E., Gordon, K.C. 1950, Ap. J. 111, 454.Google Scholar
Lucy, L.B., White, R.L. 1980, Ap. J. 241, 300.CrossRefGoogle Scholar
McLean, I.S. 1980, Ap. J. 236, L149.CrossRefGoogle Scholar
Moffat, A.F.J. 1982, this symposium.Google Scholar
Moffat, A.F.J., Seggewiss, W. 1979, A & A 77, 128.Google Scholar
Moffat, A.F.J., Seggewiss, W. 1980, A & A 86, 87.Google Scholar
Münch, G. 1950, Ap. J. 112, 266.Google Scholar
Prilutskii, O.F., Usov, V.V. 1976, Sov. Astron. 20, 2.Google Scholar
Pullavicini, R. et al. 1981, Ap. J. 248, 279.Google Scholar
Vaiana, G.S. et al. 1981, Ap. J. 245, 163.Google Scholar