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Publications

Publications by CTM

2018

Status of the Mid-IR ELT Imager and Spectrograph (METIS)

Authors
Brandl, BR; Absil, O; Agocs, T; Baccichet, N; Bertram, T; Bettonvil, F; van Boekel, R; Burtscher, L; van Dishoeck, E; Feldt, M; Garcia, PJV; Glasse, A; Glauser, A; Guedel, M; Haupt, C; Kenworthy, MA; Labadie, L; Laun, W; Lesman, D; Pantin, E; Quanz, SP; Snellen, I; Siebenmorgen, R; van Winckel, H;

Publication
GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VII

Abstract
METIS is one of the first three scientific instruments on the ELT, expected to see first light in 2025. METIS will provide diffraction limited imaging, coronagraphy, and low resolution slit spectroscopy over the 3 - 19 mu m range. Furthermore, METIS will provide a unique combination of high resolution (R similar to 100,000) integral field spectroscopy and coronagraphy from 2.9 - 5.3 mu m. The latter can be reconfigured to obtain a wider instantaneous wavelength coverage in exchange for integral field coverage. While METIS is a multi-purpose instrument for a wide range of infrared astronomy, its greatest strengths will be in the studies of exoplanets and proto-planetary disks. After two years into the preliminary design phase, the design of METIS has reached an advanced stage. This paper provides an update on the areas which have most advanced in the recent past: the main science drivers, the optical and opto-mechanical design, adaptive optics and the coronagraphy concept. We also describe the calibration of the instrument, give an overview of its observation modes, and present the schedule toward first light.

2018

Maximizing the community exploitation of the VLTI 2nd-generation instruments

Authors
Kraus, S; Garcia, P; Perrin, G;

Publication
Experimental Astronomy

Abstract

2018

Mind the gap: bridging the transversal and transferable skills chasm in a public engineering school

Authors
Freitas, A; Garcia, P; Lopes, H; de Sousa, A;

Publication
2018 3RD INTERNATIONAL CONFERENCE OF THE PORTUGUESE SOCIETY FOR ENGINEERING EDUCATION (CISPEE)

Abstract
Transversal and transferable skills are the single most important skill gap identified by employers of engineering graduates. This gap can be a very effective chasm in the early careers of otherwise competent graduates. In this paper we address the end-toend implementation of a transversal and transferable skills training programme in an European public engineering school. The training addresses master and doctoral candidates. The needs assessment, the programme design, delivery and assessment are presented. Relevant stakeholders are involved throughout. They include employers, master and doctoral candidates, faculty, graduate course directors and teaching staff directly involved in the programme. The programme includes methodologies of self-evaluation and course evolution. It is found that the programme is perceived as very important by the trainees and that there is an increasing number of enrolled trainees. The challenges of a sustained delivery of such a growing programme are shortly addressed.

2018

Methods for multiple-telescope beam imaging and guiding in the near-infrared

Authors
Anugu, N; Amorim, A; Gordo, P; Eisenhauer, F; Pfuhl, O; Haug, M; Wieprecht, E; Wiezorrek, E; Lima, J; Perrin, G; Brandner, W; Straubmeier, C; Le Bouquin, JB; Garcia, PJV;

Publication
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Abstract
Atmospheric turbulence and precise measurement of the astrometric baseline vector between any two telescopes are two major challenges in implementing phase-referenced interferometric astrometry and imaging. They limit the performance of a fibre-fed interferometer by degrading the instrument sensitivity and the precision of astrometric measurements and by introducing image reconstruction errors due to inaccurate phases. A multiple-beam acquisition and guiding camera was built to meet these challenges for a recently commissioned four-beam combiner instrument, GRAVITY, at the European Southern Observatory Very Large Telescope Interferometer. For each telescope beam, it measures (a) field tip-tilts by imaging stars in the sky, (b) telescope pupil shifts by imaging pupil reference laser beacons installed on each telescope using a 2x2 lenslet and (c) higher-order aberrations using a 9x9 Shack-Hartmann. The telescope pupils are imaged to provide visual monitoring while observing. These measurements enable active field and pupil guiding by actuating a train of tip-tilt mirrors placed in the pupil and field planes, respectively. The Shack-Hartmann measured quasi-static aberrations are used to focus the auxiliary telescopes and allow the possibility of correcting the non-common path errors between the adaptive optics systems of the unit telescopes and GRAVITY. The guiding stabilizes the light injection into single-mode fibres, increasing sensitivity and reducing the astrometric and image reconstruction errors. The beam guiding enables us to achieve an astrometric error of less than 50 mu as. Here, we report on the data reduction methods and laboratory tests of the multiple-beam acquisition and guiding camera and its performance on-sky.

2018

Physical parameters and +/- 0.2% parallax of the detached eclipsing binary V923 Scorpii

Authors
Pribulla, T; Merand, A; Kervella, P; Cameron, C; Deen, C; Garcia, PJV; Horrobin, M; Matthews, JM; Moffat, AFJ; Pfuhl, O; Rucinski, SM; Straub, O; Weiss, WW;

Publication
ASTRONOMY & ASTROPHYSICS

Abstract
Context. V923 Sco is a bright (V = 5.91), nearby (pi = 15.46 +/- 0.40 mas) southern eclipsing binary. Because both components are slow rotators, the minimum masses of the components are known with 0.2% precision from spectroscopy. The system seems ideal for very precise mass, radius, and luminosity determinations and, owing to its proximity and long orbital period (similar to 34.8 days), promises to be resolved with long-baseline interferometry. Aims. The principal aim is very accurate determinations of absolute stellar parameters for both components of the eclipsing binary and a model-independent determination of the distance. Methods. New high-precision photometry of both eclipses of V923 Sco with the MOST satellite was obtained. The system was spatially resolved with the VLTI AMBER, PIONIER, and GRAVITY instruments at nine epochs. Combining the projected size of the spectroscopic orbit (in km) and visual orbit (in mas) the distance to the system is derived. Simultaneous analysis of photometric, spectroscopic, and interferometric data was performed to obtain a robust determination of the absolute parameters. Results. Very precise absolute parameters of the components were derived in spite of the parameter correlations. The primary component is found to be overluminous for its mass. Combining spectroscopic and interferometric observations enabled us to determine the distance to V923 Sco with better than 0.2% precision, which provides a stringent test of Gaia parallaxes. Conclusions. It is shown that combining spectroscopic and interferometric observations of nearby eclipsing binaries can lead to extremely accurate parallaxes and stellar parameters.

2017

Enabling Broadband Internet Access Offshore using Tethered Balloons: The BLUECOM plus experience

Authors
Teixeira, FB; Oliveira, T; Lopes, M; Leocadio, C; Salazar, P; Ruela, J; Campos, R; Ricardo, M;

Publication
OCEANS 2017 - ABERDEEN

Abstract
The growth of the Blue Economy has been boosted by a set of traditional and new activities including maritime transportation, fisheries, environmental monitoring, deep sea mining, and inspection missions. These activities are urging for a cost-effective broadband communications solution capable of supporting both above and underwater missions at remote ocean areas, since many of them rely on an ever-increasing number of Autonomous Surface Vehicles (ASV), Autonomous Underwater Vehicles (AUV) and Remote Operated Vehicles (ROV), which need to transmit large amounts of data to shore. The BLUE-COM+ project has considered the usage of helium balloons to increase the antenna height, and overtake the earth curvature and achieve Fresnel zone clearance, combined with the use of sub-GHz frequency bands to enable long range communications. In this paper we present the results obtained in three sea trials. They show that the BLUECOM+ architecture is capable of supporting human and system activities at remote ocean areas by enabling Internet access beyond 50 km from shore, live video conference calls with the quality of experience available on land, and real-time data upload to the cloud by ASVs, AUVs and ROVs using standard access technologies with bitrates above 1 Mbit/s.

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