Damien Bonneau

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We present spectrally resolved interferometry of the Be star γ Cas in '88, '91, '93 and '94, obtained with the GI2T in-terferometer. The analysis of high spatial resolution data across the Hα line reveals azimuthally asymmetric variations which are correlated with those of V/R of the Hα profile. This correlation supports a prograde one-armed oscillation(More)
We report the first spectrally-resolved observations of the Be star γ Cas in the He i λ6678 and Hβ emission lines using the Grand Interféromètrè a 2 Télescopes in the southern France. Milliarcsecond angular resolution measurements were carried in both lines and their neighbouring continuum during October and November 1993. The He i λ6678 and Hβ maximum(More)
Context. Among optical stellar interferometers, the CHARA Array located at Mt Wilson in California offers the potential of very long baselines (up to 330 m) and the prospect of coupling multiple beam combiners. This paper presents the principle and the measured performance of VEGA, Visible spEctroGraph and polArimeter installed in September 2007 at the(More)
Context. Interferometry can provide spatially resolved observations of massive star binary systems and their colliding winds, which thus far have been studied mostly by means of spatially unresolved observations. Aims. In this work, we present the first AMBER/VLTI observations, taken at orbital phase 0.32, of the Wolf-Rayet and O (WR+O) star binary system γ(More)
Long baseline interferometric observations of δ Cep at the " Grand Interféromètrè a deux Télescopes " give the first measurement of its mean angular diameter. Combined with the mean linear radius deduced from spectroscopic data, the mean angular diameter gives an improved distance determination for δ Cep. Size pulsations are marginally detected and the(More)
We generate photon pairs in a-Si:H microrings using a CW pump, and find the Kerr coefficient of a-Si:H to be 3.73 ± 0.25 × 10-17m2/W. By measuring the Q factor with coupled power we find that the loss in the a-Si:H micro-rings scales linearly with power, and therefore cannot originate from two photon absorption. Theoretically comparing a-Si:H and c-Si(More)
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