The 2nd generation VLTI path to performance

Woillez, J.; Alonso, Jaime; Berger, J.‐P.; Bonnet, Henri; Wit, W. J. de; Egner, Sebastian; Eisenhauer, F.; Gonté, Frederic; Guieu, S.; Haguenauer, Pierre; Mérand, A.; Pettazzi, Lorenzo; Poupar, Sébastien; Schöller, M.; Schuhler, Nicolas

doi:10.1117/12.2233971

Cited by 6 publications

(3 citation statements)

References 16 publications

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“…The VLTI is a near-infrared interferometric facility located at Cerro Paranal, Chile, which offers similar capabilities as CHARA when it comes to detecting faint binary companions, with a sparser (u, v) coverage per snapshot, four-telescope observation, but with larger telescopes and generally much better observing conditions (Mérand 2018;Woillez et al 2018). The observations used here were taken with the four movable 1.8 m Auxiliary Telescopes (ATs), each equipped with an AO system, in the "large" configuration (maximum baseline ∼130 m), translating to B 2 1 .…”

Section: Vltimentioning

confidence: 99%

The CHARA Array Interferometric Program on the Multiplicity of Classical Be Stars: New Detections and Orbits of Stripped Subdwarf Companions

Klement,

Rivinius,

Gies

et al. 2024

ApJ

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Rapid rotation and nonradial pulsations enable Be stars to build decretion disks, where the characteristic line emission forms. A major but unconstrained fraction of Be stars owe their rapid rotation to mass and angular momentum transfer in a binary. The faint, stripped companions can be helium-burning subdwarf OB-type stars (sdOBs), white dwarfs (WDs), or neutron stars. We present optical/near-infrared Center for High Angular Resolution Astronomy (CHARA) interferometry of 37 Be stars selected for spectroscopic indications of low-mass companions. From multiepoch H- and/or K-band interferometry plus radial velocities and parallaxes collected elsewhere, we constructed 3D orbits and derived flux ratios and absolute dynamical masses of both components for six objects, quadrupling the number of anchor points for evolutionary models. In addition, a new wider companion was identified for the known Be + sdO binary 59 Cyg, while auxiliary Very Large Telescope Interferometer/GRAVITY spectrointerferometry confirmed circumstellar matter around the sdO companion to HR 2142. On the other hand, we failed to detect any companion to the six Be stars with γ Cas–like X-ray emission, with sdOB and main-sequence companions of the expected spectroscopic mass being ruled out for the X-ray-prototypical stars γ Cas and π Aqr, leaving elusive WDs as the most likely companions, as well as a likely explanation of the X-rays. No low-mass main-sequence close companions were identified for the other stars.

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Section: Vltimentioning

confidence: 99%

The CHARA Array Interferometric Program on the Multiplicity of Classical Be Stars: New Detections and Orbits of Stripped Subdwarf Companions

Klement,

Rivinius,

Gies

et al. 2024

ApJ

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“…The seeing, which represents the integrated strength of the turbulence along the line of sight, is the parameter used systematically for any instrument at the VLT to constrain the turbulence conditions, and this quantity can evolve rapidly in a matter of minutes. In addition, the use of adaptive optics (AO) systems at the VLT has expanded significantly in the past 3 years: all VLTI instruments are now AO-fed 2,3 and Unit Telescope 4 is a fully adaptive telescope. 4 In terms of operations, this means that new turbulence parameters have to be considered to ensure that these systems deliver their full performance.…”

Section: Supporting the Night Astronomer In Decision-making At Nightmentioning

confidence: 99%

Nowcasting the turbulence at the Paranal Observatory

Milli¹,

Gonzalez²,

Fluxa³

et al. 2019

Preprint

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At Paranal Observatory, the least predictable parameter affecting the short-term scheduling of astronomical observations is the optical turbulence, especially the seeing, coherence time and ground layer fraction. These are critical variables driving the performance of the instruments of the Very Large Telescope (VLT), especially those fed with adaptive optics systems. Currently, the night astronomer does not have a predictive tool to support him/her in decision-making at night. As most service-mode observations at the VLT last less than two hours, it is critical to be able to predict what will happen in this time frame, to avoid time losses due to sudden changes in the turbulence conditions, and also to enable more aggressive scheduling. We therefore investigate here the possibility to forecast the turbulence conditions over the next two hours. We call this "turbulence nowcasting", analogously with weather nowcasting, a term already used in meteorology coming from the contraction of "now" and "forecasting". We present here the results of a study based on historical data of the Paranal Astronomical Site Monitoring combined with ancillary data, in a machine learning framework. We show the strengths and shortcomings of such an approach, and present some perspectives in the context of the Extremely Large Telescope.

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“…The Paranal site has also an excellent median seeing of 0.8" in the visible domain, and clear skies all over the year. In addition, the arrival of the second-generation instruments of the VLTI triggered a thorough assessment and improvement of the VLTI infrastructure performance [30,31], making relevant the perspective of a visible addition to the VLTI instruments suite.…”

Section: Unique Science That Can Be Done At Vlti In the Visiblementioning

confidence: 99%