Optical spectroscopy of Be/gamma-ray binaries

Abstract

We report optical spectroscopic observations of the Be/gamma-ray binaries LSI+61303, MWC 148 and MWC 656. The peak separation and equivalent widths of prominent emission lines (H-alpha, H-beta, H-gamma, HeI, and FeII) are measured. We estimated the circumstellar disc size, compared it with separation between the components, and discussed the disc truncation. We find that in LSI+61303 the compact object comes into contact with the outer parts of the circumstellar disc at periastron, in MWC 148 the compact object goes deeply into the disc during the periastron passage, and in MWC 656 the black hole is accreting from the outer parts of the circumstellar disc along the entire orbit. The interstellar extinction was estimated using interstellar lines. The rotation of the mass donors appears to be similar to the rotation of the mass donors in Be/X-ray binaries. We suggest that X-ray/optical periodicity of about 1 day deserves to be searched for.

9 pages, accepted in A&A

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Cited by in corpus (15)

• On the relationship between circumstellar disc size and X-ray outbursts in Be/X-ray binaries
• MWC 656 is unlikely to contain a black hole
• GeV detection of HESS J0632+057
• Observation of the gamma-ray binary HESS J0632+057 with the H.E.S.S., MAGIC, and VERITAS telescopes
• Optical spectroscopy of Be/gamma-ray binaries
• Spectral observations of X Persei: Connection between H-alpha and X-ray emission
• Superorbital modulation at GeV energies in the gamma-ray binary LS I +61 303
• Optical spectroscopy of the Be/X-ray Binary V850 Cen/GX 304-1 during faint X-ray periodical activity
• Probing the Properties of the Pulsar Wind in the Gamma-Ray Binary HESS J0632+057 with NuSTAR and VERITAS Observations
• Multi-Wavelength Observation Campaign of the TeV Gamma-Ray Binary HESS J0632+057 with NuSTAR, VERITAS, MDM, and Swift
• Radius, rotational period and inclination of the Be stars in the Be/gamma-ray binaries MWC 148 and MWC 656
• Optical spectroscopy of the Be/black hole binary MWC656 -- interaction of a black hole with a circumstellar disc
• Optical and Near-Infrared Monitoring of Gamma-ray Binaries Hosting Be Stars
• Optical spectroscopy of Be stars: peak separation of Balmer emission lines
• Characterizing the VHE emission of LS I +61 303 using VERITAS observations