Spatial filtering in AMBER

Mège, P.; Malbet, Fabien; Chelli, A.

doi:10.1117/12.390198

Cited by 7 publications

(4 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The instrument uses spatial filtering with fibers (Mege et al 2000). The interferometric beam passes through anamorphic optics compressing the beam perpendicularly to the fringe coding in order to be injected into the slit of a spectrograph.…”

Section: Observationsmentioning

confidence: 99%

Direct constraint on the distance of γ² Velorum from AMBER/VLTI observations

Millour

Petrov

Chesneau

et al. 2006

A&A

View full text Add to dashboard Cite

Context. Interferometry can provide spatially resolved observations of massive star binary systems and their colliding winds, which thus far have been studied mostly with spatially unresolved observations. Aims. 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 2 Velorum and use the interferometric observables to constrain its properties. Methods. The AMBER/VLTI instrument was used with the telescopes UT2, UT3, and UT4 on baselines ranging from 46 m to 85 m. It delivered spectrally dispersed visibilities, as well as differential and closure phases, with a resolution R = 1500 in the spectral band 1.95−2.17 µm. We interpret these data in the context of a binary system with unresolved components, neglecting in a first approximation the wind-wind collision zone flux contribution. Results. Using WR-and O-star synthetic spectra, we show that the AMBER/VLTI observables result primarily from the contribution of the individual components of the WR+O binary system. We discuss several interpretations of the residuals, and speculate on the detection of an additional continuum component, originating from the free-free emission associated with the wind-wind collision zone (WWCZ), and contributing at most to the observed K-band flux at the 5% level. Based on the accurate spectroscopic orbit and the Hipparcos distance, the expected absolute separation and position angle at the time of observations were 5.1 ± 0.9 mas and 66 ± 15• , respectively. However, using theoretical estimates for the spatial extent of both continuum and line emission from each component, we infer a separation of 3.62 +0.11 −0.30 mas and a position angle of 73• , compatible with the expected one. Our analysis thus implies that the binary system lies at a distance of 368 +38 −13 pc, in agreement with recent spectrophotometric estimates, but significantly larger than the Hipparcos value of 258 +41 −31 pc.

show abstract

Section: Observationsmentioning

confidence: 99%

Direct constraint on the distance of γ² Velorum from AMBER/VLTI observations

Millour

Petrov

Chesneau

et al. 2006

A&A

View full text Add to dashboard Cite

show abstract

“…To be efficient, the spatial filter must transmit at least 10 3 more light in the guided mode than in all the secondary modes. For the kind of imperfect AO correction (Strehl ratios often < 50%) available for the VLTI, the single way to achieve such high filtering quality with decent light transmission is to use single mode optical fibers [17] (-6-in figure 1). The flux transmitted by each filter must be monitored in real time in each spectral channel.…”

Section: Basic Concept Of Ambermentioning

confidence: 99%

AMBER: a near infrared focal instrument for the VLTI

Petrov¹,

Malbet²,

Richichi³

et al. 2001

Comptes Rendus de l'Académie des Sciences - Series IV - Physics

Self Cite

View full text Add to dashboard Cite

RESUMEAMBER est l' instruments focal proche infra rouge du mode interférométrique du Très Grand Télescope Européen. Les spécifications de cet instrument généraliste ont été définies pour trois programmes clefs sur les systèmes stellaires en formation, les régions centrales des noyaux actifs de galaxies et les masses et les spectres de planètes extra solaires géantes chaudes. Il combine trois faisceaux, ce qui lui donne une capacité de reconstruction d' images, et est optimisé pour la précision des mesures grâce à un filtrage spatial des faisceaux par des fibres optiques mono mode et à une combinaison des informations obtenues simultanément à différentes longueurs d' onde. ABSTRACTAMBER is the General User near infrared focal instrument of the Very Large Telescope Interferometer. Its specifications are based on three key programs on Young Stellar Objects, Active Galactic Nuclei central regions, masses and spectra of hot Extra Solar Planets. It has an imaging capacity because it combines up to three beams and very high accuracy measurement are expected from the spatial filtering of beams by single mode fibers and the comparison of measurements made simultaneously in different spectral channels. * Correspondence: e_mail: petrov@unice.fr; Telephone: 33 4 92 07 63 47; Fax: 33 4 92 07 63 21.

show abstract

“…1 The instrument uses spatial filtering with fibers. 2 The interferometric beam passes through anamorphic optics compressing the beam perpendicularly to the fringe coding in order to be injected into the slit of a spectrograph. The instrument can operate at spectral resolutions of 35, 1500 and 10,000, and efficiently deliver spectrally dispersed visibilities, closure phases and differential phases.…”

Section: Introductionmentioning

confidence: 99%

Wolf-Rayet stars probed by AMBER/VLTI

Millour,

Chesneau,

Driebe

et al. 2008

Preprint

View full text Add to dashboard Cite

Massive stars deeply influence their surroundings by their luminosity and the injection of kinetic energy. So far, they have mostly been studied with spatially unresolved observations, although evidence of geometrical complexity of their wind are numerous. Interferometry can provide spatially resolved observations of massive stars and their immediate vicinity. Specific geometries (disks, jets, latitude-dependent winds) can be probed by this technique.The first observation of a Wolf-Rayet (WR) star (γ 2 Vel) with the AMBER/VLTI instrument yielded to a re-evaluation of its distance and an improved characterization of the stellar components, from a very limited data-set. This motivated our team to increase the number of WR targets observed with AMBER. We present here new preliminary results that encompass several spectral types, ranging from early WN to evolved dusty WC.We present unpublished data on WR79a, a massive star probably at the boundary between the O and Wolf-Rayet type, evidencing some Wolf-Rayet broad emission lines from an optically thin wind. We also present new data obtained on γ 2 Vel that can be compared to the up-to-date interferometry-based orbital parameters from North et al. (2007). We discuss the presence of a wind-wind collision zone in the system and provide preliminary analysis suggesting the presence of such a structure in the data. Then, we present data obtained on 2 dusty Wolf-Rayet stars: WR48a-b and WR118, the latter exhibiting some clues of a pinwheel-like structure from the visibility variations.

show abstract

Spatial filtering in AMBER

Cited by 7 publications

References 6 publications

Direct constraint on the distance of γ² Velorum from AMBER/VLTI observations

Direct constraint on the distance of γ² Velorum from AMBER/VLTI observations

AMBER: a near infrared focal instrument for the VLTI

Wolf-Rayet stars probed by AMBER/VLTI

Contact Info

Product

Resources

About

Spatial filtering in AMBER

Cited by 7 publications

References 6 publications

Direct constraint on the distance of γ2 Velorum from AMBER/VLTI observations

Direct constraint on the distance of γ2 Velorum from AMBER/VLTI observations

AMBER: a near infrared focal instrument for the VLTI

Wolf-Rayet stars probed by AMBER/VLTI

Contact Info

Product

Resources

About

Direct constraint on the distance of γ² Velorum from AMBER/VLTI observations

Direct constraint on the distance of γ² Velorum from AMBER/VLTI observations