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J. Sahlmann,
T. Henning,
D. Queloz,
A. Quirrenbach,
N. M. Elias II,
R. Launhardt,
F. Pepe,
S. Reffert,
D. Segransan,
J. Setiawan, [......],
C. Schmid,
N. Schuhler,
T. Schulze-Hartung,
D. Sosnowska,
B. Tubbs,
G. T. van Belle,
K. Wagner,
L. Weber,
L. Zago,
N. Zimmerman
[show abstract]
[hide abstract]
ABSTRACT: The ESPRI project relies on the astrometric capabilities offered by the PRIMA
facility of the Very Large Telescope Interferometer for the discovery and study
of planetary systems. Our survey consists of obtaining high-precision
astrometry for a large sample of stars over several years and to detect their
barycentric motions due to orbiting planets. We present the operation
principle, the instrument's implementation, and the results of a first series
of test observations. A comprehensive overview of the instrument infrastructure
is given and the observation strategy for dual-field relative astrometry is
presented. The differential delay lines, a key component of the PRIMA facility
which was delivered by the ESPRI consortium, are described and their
performance within the facility is discussed. Observations of bright visual
binaries are used to test the observation procedures and to establish the
instrument's astrometric precision and accuracy. The data reduction strategy
for astrometry and the necessary corrections to the raw data are presented.
Adaptive optics observations with NACO are used as an independent verification
of PRIMA astrometric observations. The PRIMA facility was used to carry out
tests of astrometric observations. The astrometric performance in terms of
precision is limited by the atmospheric turbulence at a level close to the
theoretical expectations and a precision of 30 micro-arcseconds was achieved.
In contrast, the astrometric accuracy is insufficient for the goals of the
ESPRI project and is currently limited by systematic errors that originate in
the part of the interferometer beamtrain which is not monitored by the internal
metrology system. Our observations led to the definition of corrective actions
required to make the facility ready for carrying out the ESPRI search for
extrasolar planets.
12/2012;
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J. Sahlmann,
D. Ségransan,
A. Mérand,
N. Zimmerman,
R. Abuter,
B. Chazelas, F. Delplancke,
T. Henning,
A. Kaminski,
R. Köhler,
R. Launhardt,
M. Mohler,
F. Pepe,
D. Queloz,
A. Quirrenbach,
S. Reffert,
C. Schmid,
N. Schuhler,
T. Schulze-Hartung
[show abstract]
[hide abstract]
ABSTRACT: The Extrasolar Planet Search with PRIMA project (ESPRI) aims at
characterising and detecting extrasolar planets by measuring the host star's
reflex motion using the narrow-angle astrometry capability of the PRIMA
facility at the Very Large Telescope Interferometer. A first functional
demonstration of the astrometric mode was achieved in early 2011. This marked
the start of the astrometric commissioning phase with the purpose of
characterising the instrument's performance, which ultimately has to be
sufficient for exoplanet detection. We show results obtained from the
observation of bright visual binary stars, which serve as test objects to
determine the instrument's astrometric precision, its accuracy, and the plate
scale. Finally, we report on the current status of the ESPRI project, in view
of starting its scientific programme.
07/2012;
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A. Glindemann,
J. Algomedo,
R. Amestica,
P. Ballester,
B. Bauvir,
E. Bugueño,
S. Correia,
F. Delgado, F. Delplancke,
F. Derie, [......],
S. Ménardi,
S. Morel,
F. Paresce,
T. Phan Duc,
A. Richichi,
M. Schöller,
M. Tarenghi,
A. Wallander,
M. Wittkowski,
R. Wilhelm
[show abstract]
[hide abstract]
ABSTRACT: The Very Large Telescope (VLT) Observatory on Cerro Paranal (2635 m) in Northern Chile is approaching completion. After the
four 8-m Unit Telescopes (UT) individually saw first light in the last years, two of them were combined for the first time
on October 30, 2001 to form a stellar interferometer, the VLT Interferometer. The combination in pairs of all four UTs was
completed in September 2002. In this article, we will describe the subsystems of the VLTI and the planning for the following
years.
Astrophysics and Space Science 04/2012; 286(1):35-44. · 1.69 Impact Factor
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J. Sahlmann,
R. Abuter,
S. Menardi,
C. Schmid,
N. di Lieto, F. Delplancke,
R. Frahm,
N. Gomes,
P. Haguenauer,
S. Leveque,
S. Morel,
A. Mueller,
T. Phan Duc,
N. Schuhler,
G. van Belle
[show abstract]
[hide abstract]
ABSTRACT: The fringe sensor unit (FSU) is the central element of the phase referenced imaging and micro-arcsecond astrometry (PRIMA) dual-feed facility for the Very Large Telescope interferometer (VLTI). It has been installed at the Paranal observatory in August 2008 and is undergoing commissioning and preparation for science operation. Commissioning observations began shortly after installation and first results include the demonstration of spatially encoded fringe sensing and the increase in VLTI limiting magnitude for fringe tracking. However, difficulties have been encountered because the FSU does not incorporate real-time photometric correction and its fringe encoding depends on polarisation. These factors affect the control signals, especially their linearity, and can disturb the tracking control loop. To account for this, additional calibration and characterisation efforts are required. We outline the instrument concept and give an overview of the commissioning results obtained so far. We describe the effects of photometric variations and beam-train polarisation on the instrument operation and propose possible solutions. Finally, we update on the current status in view of the start of astrometric science operation with PRIMA. Comment: 12 pages, 11 figures, SPIE 2010 conference proceedings
12/2010;
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P Haguenauer,
J Alonso,
P Bourget,
S Brillant,
P Gitton,
S Guisard,
S Poupar,
N Schuhler,
R Abuter,
L Andolfato, [......],
A Richichi,
T Rivinius,
J Sahlmann,
M Schoeller,
C Schmid,
S Stefl,
G Valdes,
G Belle,
S Wehner,
M Wittkowski
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series; 07/2010
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F. Malbet,
A. Sozzetti,
P. Lazorenko,
R. Launhardt,
D. Segransan, F. Delplancke,
N. Elias,
M. Muterspaugh,
A. Quirrenbach,
S. Reffert,
G. van Belle
[show abstract]
[hide abstract]
ABSTRACT: The astrometry technique is an important tool for detecting and characterizing exoplanets of different type. In this review, the different projects which are either operating, in construction or in discussion are presented and their performance discussed in the framework of the Blue Dots study. We investigate the sensitivity of astrometry to different sources of noise and we show that astrometry is a key technique in the path of discovering and characterizing new types of planets including the very challenging category of Earth-like planets orbiting the habitable zone of solar-type stars. Comment: 9 pages, to be published in the proceedings of the "Pathways Towards Habitable Planets" conference, held in Barcelona (14-18 Sep 2009)
12/2009;
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[show abstract]
[hide abstract]
ABSTRACT: The Very Large Telescope Interferometer (VLTI, see Fig.90.1) in its basic configuration of four 8m and four 1.8m telescopes,
spanning baselines between 8m and 200m, will be at the forefront of infrared interferometry for at least the coming two
decades. It is currently the only interferometer which gives access to closure phases and more than one baseline with 8m-class
telescopes. Arguably, it is also the only existing interferometer which can easily adapt to different science cases with its
movable smaller telescopes. Its suite of current and envisioned instruments is absolutely unique and unlike other interferometers
it has a large user base, running in the VLT operations model.
12/2008: pages 501-506;
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H. Bartko,
O. Pfuhl,
F. Eisenhauer,
R. Genzel,
S. Gillessen,
S. Rabien,
R. Abuter,
G. v. Belle, F. Delplancke,
S. Menardi,
J. Sahlmann
[show abstract]
[hide abstract]
ABSTRACT: The Phase-Referenced Imaging and Micro-arcsecond Astrometry (PRIMA) facility is scheduled for installation in the Very Large Telescope Interferometer observatory in Paranal, Chile, in the second half of 2008. Its goal is to provide astrometric accuracy in the micro-arcsecond range. High precision astrometry can be applied to explore the dynamics of the dense stellar cluster. Especially models for the formation of stars near super massive black holes or the fast transfer of short-lived massive stars into the innermost parsec of our galaxy can be tested. By measuring the orbits of stars close to the massive black hole one can probe deviations from a Keplerian motion. Such deviations could be due to a swarm of dark, stellar mass objects that perturb the point mass solution. At the same time the orbits are affected by relativistic corrections which thus can be tested. The ultimate goal is to test the effects of general relativity in the strong gravitational field. The latter can be probed with the near infrared flares of SgrA* which are most likely due to accretion phenomena onto the black hole. We study the expected performance of PRIMA for astrometric measurements in the Galactic Center based on laboratory measurements and discuss possible observing strategies. Comment: Presentation at the SPIE 2008 conference "Optical and Infrared Interferometry"
07/2008;
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F. Pepe,
D. Queloz,
Th. Henning,
A. Quirrenbach, F. Delplancke,
L. Andolfato,
H. Baumeister,
P. Bizenberger,
H. Bleuler,
B. Chazelas, [......],
Y. Michellod,
J. M. Moresmau,
P. Müllhaupt,
V. Naranjo,
L. Sache,
Y. Salvadé,
G. Simond,
D. Sosnowska,
K Wagner,
L. Zago
[show abstract]
[hide abstract]
ABSTRACT: ESPRI is a project which aims at searching for and characterizing extra-solar planets by dual-beam astrometry with PRIMA@VLTI. Differential Delay Lines (DDL) are fundamental for achieving the micro-arcseconds accuracy required by the scientific objective. Our Consortium, consisting of the Geneva Observatory, the Max-Planck Institut for Astronomy Heidelberg, and the Landessternwarte Heidelberg, in collaboration with ESO, has built and tested these DDLs successfully and will install them in summer 2008 at the VLTI. These DDLs consist of high quality cat's eyes displaced on a parallel beam-mechanics and by means of a two-stage actuation with a precision of 5 nm over a stroke length of 70 mm. Over the full range, a bandwidth of about 400 Hz is achieved. The DDLs are operated in vacuum. We shall present, in this paper, their design and their exceptional performances.
Schöller, Markus; Danchi, William C.; Delplancke, Francoise: Optical and Infrared Interferometry, SPIE, 70130P-12 (2008). 07/2008;
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R. Launhardt,
D. Queloz,
Th. Henning,
A. Quirrenbach, F. Delplancke,
L. Andolfato,
H. Baumeister,
P. Bizenberger,
H. Bleuler,
B. Chazelas, [......],
T. Schulze-Hartung,
J. Setiawan,
G. Simond,
D. Sosnowska,
I. Stilz,
B. Tubbs,
K Wagner,
L. Weber,
P. Weise,
L. Zago
[show abstract]
[hide abstract]
ABSTRACT: PRIMA, the instrument for Phase-Referenced Imaging and Micro-arcsecond Astrometry at the VLTI, is currently being developed at ESO. PRIMA will implement the dual-feed capability, at first for two UTs or ATs, to enable simultaneous interferometric observations of two objects that are separated by up to 1 arcmin. PRIMA is designed to perform narrow-angle astrometry in K-band with two ATs as well as phase-referenced aperture synthesis imaging with instruments like Amber and Midi. In order to speed up the full implementation of the 10 microarcsec astrometric capability of the VLTI and to carry out a large astrometric planet search program, a consortium lead by the Observatoire de Genève, Max Planck Institute for Astronomy, and Landessternwarte Heidelberg, has built Differential Delay Lines for PRIMA and is developing the astrometric observation preparation and data reduction software. When the facility becomes fully operational in 2009, we will use PRIMA to carry out a systematic astrometric Exoplanet Search program, called ESPRI. In this paper, we describe the narrow-angle astrometry measurement principle, give an overview of the ongoing hardand software developments, and outline our anticipated astrometric exoplanet search program.
Schöller, Markus; Danchi, William C.; Delplancke, Francoise: Optical and Infrared Interferometry, SPIE, 70132I-70132I-10 (2008). 07/2008;
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R. Launhardt,
E. J. Bakker,
P. Ballester,
H. Baumeister,
P. Bizenberger,
H. Bleuler,
R. Dändliker, F. Delplancke,
F. Derie,
M. Fleury, [......],
Y. Salvadé,
O. Scherler,
D. Ségransan,
J. Setiawan,
D. Sosnowska,
R. N. Tubbs,
L. Venema,
K. Wagner,
L. Weber,
R. Wüthrich
02/2008: pages 551-553;
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P. Gondoin,
R. den Hartog,
M. Fridlund,
P. Fabry,
A. Stankov,
A. Peacock,
S. Volonte,
F. Puech, F. Delplancke,
P. Gitton, [......],
K. Ergenzinger,
A. Quirrenbach,
O. Wallner,
J. Alves,
T. Herbst,
D. Mourard,
R. Neuhäuser,
D. Ségransan,
R. Waters,
G.J. White
[show abstract]
[hide abstract]
ABSTRACT: Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives
are to detect Earth-like planets around nearby stars, to analyze the composition of their atmospheres and to assess their
ability to sustain life as we know it. Darwin is conceived as a space “nulling interferometer” which makes use of on-axis
destructive interferences to extinguish the stellar light while keeping the off-axis signal of the orbiting planet. Within
the frame of the Darwin program, definition studies of a Ground based European Nulling Interferometry Experiment, called GENIE,
were completed in 2005. This instrument built around the Very Large Telescope Interferometer (VLTI) in Paranal will test some
of the key technologies required for the Darwin Infrared Space Interferometer. GENIE will operate in the L’ band around 3.8
microns as a single Bracewell nulling interferometer using either two Auxiliary Telescopes (ATs) or two 8m Unit Telescopes
(UTs). Its science objectives include the detection and characterization of dust disks and low-mass companions around nearby
stars.
12/2007: pages 445-456;
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M Schöller,
J Argomedo,
B Bauvir,
L Blanco-Lopez,
H Bonnet,
S Brillant,
M Cantzler,
J Carstens,
F Caruso,
C Choque-Cortez, [......],
S Stefl,
V Suc,
R Tamai,
M Tapia,
M Vannier,
G Vasisht,
A Wallander,
S Wehner,
M Wittkowski,
J Zagal
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series; 07/2006
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[show abstract]
[hide abstract]
ABSTRACT: The mature life of the VLT Interferometer and its instrumentation will start with the availability of the PRIMA dual feed
facility. Possible extensions of this latter might also be developed for use with second generation instrumentation, making
it possible to combine and phase-reference several beams simultaneously. The introduction of the dual feed in interferometry
will create a situation similar to that already experienced in Adaptive Optics, namely the fact that most scientific programs
will be limited by the availability of a suitable reference star nearby. With sufficient time available ahead of us, we propose
to turn the problem around and investigate the surroundings of a large number of suitably bright reference stars, to compile
a list of interesting objects which could be studied by the VLTI and its dual feed facility. This would permit to obtain accurate
astrometry and/or detailed imaging of objects such as brown dwarfs, (micro)gravitational lenses, extragalactic sources. We
discuss the needs and strategies to investigate the surroundings of a number of bright stars, using available near-IR surveys,
as well as novel dedicated observations.
02/2006: pages 311-313;
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R. Launhardt,
H. Baumeister,
P. Bizenberger,
T. Henning,
J. Setiawan,
K. Wagner,
W. Jaffe,
J. de Jong,
R. Kohler,
R. Mathar, [......],
O. Scherler,
H. Hanenburge,
K. Murakawa,
J. Pragt, F. Delplancke,
F. Derie,
L. Venema,
P. Ballester,
A. Glindenmann,
R. Tubbs
Protostars and Planets V, Hilton waikola Village, Hawai; 08/2005
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A Glindemann,
M Albertsen,
L Andolfato,
G Avila,
P Ballester,
B Bauvir, F Delplancke,
F Derie,
M Dimmler,
P Duhoux, [......],
A Richichi,
C Sabet,
K ~L Scales,
M Schoeller,
N Schuhler,
M Ancker,
M Vannier,
A Wallander,
M Wittkowski,
R ~C Wilhelm
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series; 10/2004
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[show abstract]
[hide abstract]
ABSTRACT: The four main scientific objectives of PRIMA – the Phase-Referenced Imaging and Micro-arc second Astrometry facility for the
VLTI – will be described:– extra-solar system characterization with astrometry, to detect planets and evaluate their mass,
and imaging of the dust accretion disk,– galactic center study with astrometry(dynamics of the bulge stars) and imaging at
10μm (piercing the gas and dust clouds surrounding the galactic center),– observations of AGNs and other extra-galactic objects,
too faint to be observed without PRIMA, for which partial imaging is needed to constrain their structuremodels,– micro-gravitational
lensing event resolution (imaging and astrometry of their photo-center) in the Galactic Bulge and Magellanic Clouds, helping
to determine directly the lens mass and distance.
Astrophysics and Space Science 07/2003; 286(1):99-104. · 1.69 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: After a brief introduction of the key scientific objectives of PRIMA,
this paper will summarize the preliminary system engineering study and
will introduce the technical baseline and implementation of the system.
Mutual benefit of GENIE and PRIMA development, in particular on the
Fringe Sensor and the Metrology, will be also discussed.
02/2003; 522:6.
-
A. Glindemann,
J. Algomedo,
R. Amestica,
P. Ballester,
B. Bauvir,
E. Bugueño,
S. Correia,
F. Delgado, F. Delplancke,
F. Derie, [......],
S. Ménardi,
S. Morel,
F. Paresce,
T. Phan Duc,
A. Richichi,
M. Schöller,
M. Tarenghi,
A. Wallander,
M. Wittkowski,
R. Wilhelm
[show abstract]
[hide abstract]
ABSTRACT: The Very Large Telescope (VLT) Observatory on Cerro Paranal (2635 m) in
Northern Chile is approaching completion. After the four 8-m Unit
Telescopes (UT) individually saw ~Arst light in the last years, two of
them were combined for the ~Arst time on October 30, 2001 to form a
stellar interferometer, the VLT Interferometer. The remaining two UTs
will be integrated into the interferometric array later this year, so
that any two UTs can be used for interferometry. In this article, we
will describe the subsystems of the VLTI and the planning for the
following years.
02/2003; 522:5.
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M Schoeller,
P ~B Gitton,
J Argomedo,
P Ballester,
B Bauvir,
R Van Boekel,
M Cantzler,
S Correia,
W ~D Cotton, F Delplancke, [......],
A Rijo,
C Sabet,
S Sandrock,
D Segransan,
J Spyromilio,
R Tamai,
M Tarenghi,
A Wallander,
R Wilhelm,
M Wittkowski
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series; 02/2003
