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Archive | 2012

Proceedings of the SPIE

Gavin Dalton; Scott Trager; Don Carlos Abrams; David Carter; P. Bonifacio; J. Alfonso L. Aguerri; Mike MacIntosh; Christopher H. Evans; Ian Lewis; Ramón Navarro; Tibor Agócs; Kevin Dee; Sophie Rousset; Ian Tosh; Kevin Middleton; J. Pragt; David Terrett; Matthew Brock; Chris R. Benn; Marc Verheijen; Diego Cano Infantes; Craige Bevil; Iain A. Steele; Chris Mottram; Stuart Bates; Francis J. Gribbin; Jürg Rey; Luis Fernando Rodriguez; Jose Miguel Delgado; Isabelle Guinouard

Wide-field multi-object spectroscopy is a high priority for European astronomy over the next decade. Most 8-10m telescopes have a small field of view, making 4-m class telescopes a particularly attractive option for wide-field instruments. We present a science case and design drivers for a wide-field multi-object spectrograph (MOS) with integral field units for the 4.2-m William Herschel Telescope (WHT) on La Palma. The instrument intends to take advantage of a future prime-focus corrector and atmospheric-dispersion corrector (Agocs et al, this conf.) that will deliver a field of view 2 deg in diameter, with good throughput from 370 to 1,000 nm. The science programs cluster into three groups needing three different resolving powers R: (1) high-precision radial-velocities for Gaia-related Milky Way dynamics, cosmological redshift surveys, and galaxy evolution studies (R = 5,000), (2) galaxy disk velocity dispersions (R = 10,000) and (3) high-precision stellar element abundances for Milky Way archaeology (R = 20,000). The multiplex requirements of the different science cases range from a few hundred to a few thousand, and a range of fibre-positioner technologies are considered. Several options for the spectrograph are discussed, building in part on published design studies for E-ELT spectrographs. Indeed, a WHT MOS will not only efficiently deliver data for exploitation of important imaging surveys planned for the coming decade, but will also serve as a test-bed to optimize the design of MOS instruments for the future E-ELT.


Proceedings of SPIE | 2012

WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope

Gavin Dalton; Scott Trager; Don Carlos Abrams; David Carter; P. Bonifacio; J. Alfonso L. Aguerri; Mike MacIntosh; C. J. Evans; Ian Lewis; Ramón Navarro; Tibor Agócs; Kevin Dee; Sophie Rousset; Ian Tosh; Kevin Middleton; J. Pragt; David Terrett; Matthew Brock; Chris R. Benn; Marc Verheijen; Diego Cano Infantes; Craige Bevil; Iain A. Steele; Chris Mottram; Stuart Bates; Francis J. Gribbin; Jürg Rey; Luis Fernando Rodriguez; Jose Miguel Delgado; Isabelle Guinouard

We present the preliminary design of the WEAVE next generation spectroscopy facility for the William Herschel Telescope (WHT), principally targeting optical ground-based follow up of upcoming ground-based (LOFAR) and spacebased (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2 degree prime focus field of view at the WHT, with a buffered pick and place positioner system hosting 1000 multi-object (MOS) fibres or up to 30 integral field units for each observation. The fibres are fed to a single spectrograph, with a pair of 8k(spectral) x 6k (spatial) pixel cameras, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000.


Proceedings of SPIE | 2010

ASTEP 400: a telescope designed for exoplanet transit detection from Dome C, Antarctica

Jean-Baptiste Daban; Carole Gouvret; Tristan Guillot; Abdelkrim Agabi; Nicolas Crouzet; Jean-Pierre Rivet; D. Mékarnia; Lyu Abe; E. Bondoux; Yan Fanteï-Caujolle; Francois Fressin; F.-X. Schmider; Franck Valbousquet; Pierre-Éric Blanc; Auguste Le Van Suu; H. Rauer; A. Erikson; Frederic Pont; S. Aigrain

The Concordia Base in Dome C, Antarctica, is an extremely promising site for photometric astronomy due to the 3- month long night during the Antarctic winter, favorable weather conditions, and low scintillation. The ASTEP project (Antarctic Search for Transiting ExoPlanets) is a pilot project which seeks to identify transiting planets and understand the limits of visible photometry from this site. ASTEP 400 is an optical 40cm telescope with a field of view of 1° x 1°. The expected photometric sensitivity is 1E-3, per hour for at least 1,000 stars. The optical design guarantees high homogeneity of the PSF sizes in the field of view. The use of carbon fibers in the telescope structure guarantees high stability. The focal optics and the detectors are enclosed in a thermally regulated box which withstands extremely low temperatures. The telescope designed to run at -80°C (-110°F) was set up at Dome C during the southern summer 2009- 2010. It began its nightly observations in March 2010.


Iau Symposia | 2008

ASTEP South: An Antarctic Search for Transiting Planets around the celestial South pole

Nicolas Crouzet; Karim Agabi; A. Blazit; Serge Bonhomme; Yan Fanteï-Caujolle; Francois Fressin; Tristan Guillot; F.-X. Schmider; Franck Valbousquet; E. Bondoux; Z. Challita; Lyu Abe; Jean-Baptiste Daban; Carole Gouvret

ASTEP South is the first phase of the ASTEP project (Antarctic Search for Transiting ExoPlanets). The instrument is a fixed 10 cm refractor with a 4kx4k CCD camera in a thermalized box, pointing continuously a 3.88° x 3.88° field of view centered on the celestial South pole. ASTEP South became fully functional in June 2008 and obtained 1592 hours of data during the 2008 Antarctic winter. The data are of good quality but the analysis has to account for changes in the point spread function due to rapid ground seeing variations and instrumental effects. The pointing direction is stable within 10 arcseconds on a daily timescale and drifts by only 34 arcseconds in 50 days. A truly continuous photometry of bright stars is possible in June (the noon sky background peaks at a magnitude R=15 arcsec-2 on June 22), but becomes challenging in July (the noon sky background magnitude is R=12.5 arcsec−2 on July 20). The weather conditions are estimated from the number of stars detected in the field. For the 2008 winter, the statistics are between 56.3 % and 68.4 % of excellent weather, 17.9 % to 30 % of veiled weather and 13.7 % of bad weather. Using these results in a probabilistic analysis of transit detection, we show that the detection efficiency of transiting exoplanets in one given field is improved at Dome C compared to a temperate site such as La Silla. For example we estimate that a year-long campaign of 10 cm refractor could reach an efficiency of 69 % at Dome C versus 45 % at La Silla for detecting 2-day period giant planets around target stars from magnitude 10 to 15. This shows the high potential of Dome C for photometry and future planet discoveries. [Short abstract]


Ground-based and Airborne Instrumentation for Astronomy VII | 2018

Design, specification, and manufacturing of a PIAACMC for the SPEED testbed

Patrice Martinez; Mathilde Beaulieu; Carole Gouvret; Julien Dejonghe; Olivier Preis; Olivier Guyon; Lyu Abe

The Phase-Induced Amplitude Apodization Complex Mask Coronagraph (PIAACMC) is a promising corona- graphic device for direct detection of exoplanets with complex segmented telescope apertures. This concept features the bright idea of generating a pupil apodization by reflection on two mirrors whose wavefront maps are specifically optimized, and a complex focal plane mask. In this paper, we report on the design, specifications, and manufacturing of such a coronagraph for the SPEED facility (Segmented Pupil Experiment for Exoplanet Detection) struggled for deep contrast at small angular separation with complex telescope aperture.


Adaptive Optics Systems VI | 2018

The segmented pupil experiment for exoplanet detection: Part 3. Advances and first light with segments cophasing

Patrice Martinez; Marina Yu. Postnikova; Carole Gouvret; Pierre Janin-Potiron; Julien Dejonghe; A. Marcotto; A. Spang; Olivier Preis; Mamadou N'Diaye; Lyu Abe; Pierre Baudoz; Mathilde Beaulieu; Olivier Guyon

SPEED (Segmented Pupil Experiment for Exoplanet Detection) is an instrumental testbed designed to offer an ideal cocoon to provide relevant solutions in both cophasing and high-contrast imaging with segmented telescopes. The next generation of observatories will be made of a primary mirror with excessive complexity (mirror segmentation, central obscuration, and spider vanes) undoubtedly known to be unfavorable for the direct detection of exoplanets. Exoplanets detection around late-type stars (M-dwarfs) constitutes an outstanding reservoir of candidates, and SPEED integrates all the recipes to pave the road for this science case (cophasing sensors, multi-DM wavefront control and shaping architecture as well as advanced coronagraphy). In this paper, we provide a progress overview of the project and report on the first light with segments cophasing control and monitoring from a coronagraphic image.


Proceedings of SPIE | 2016

SPEED design optimization via Fresnel propagation analysis

Mathilde Beaulieu; Lyu Abe; Patrice Martinez; Carole Gouvret; Julien Dejonghe; Oliver Preis; F. Vakili

Future extremely large telescopes will open a niche for exoplanet direct imaging at the expense of using a primary segmented mirror which is known to hamper high-contrast imaging capabilities. The focal plane diffraction pattern is dominated by bright structures and the way to reduce them is not straightforward since one has to deal with strong amplitude discontinuities in this kind of unfriendly pupil (segment gaps and secondary support). The SPEED experiment developed at Lagrange laboratory is designed to address this specific topic along with high-contrast at very small separation. The baseline design of SPEED will combine a coronagraph and two deformable mirrors to create dark zones at the focal plane. A first step in this project was to identify under which circumstances the deep contrast at small separation is achievable. In particular, the DMs location is among the critical aspect to consider and is the topic covered by this paper.


arXiv: Instrumentation and Methods for Astrophysics | 2012

ASTEP South: A first photometric analysis

Nicolas Crouzet; Tristan Guillot; D. Mékarnia; J. Szulágyi; Lyu Abe; Abdelkrim Agabi; Yan Fanteï-Caujolle; I. Gonçalves; M. Barbieri; F.-X. Schmider; Jean-Pierre Rivet; E. Bondoux; Z. Challita; C. Pouzenc; Francois Fressin; F. Valbousquet; A. Blazit; Serge Bonhomme; Jean-Baptiste Daban; Carole Gouvret; D. Bayliss; G. Zhou

The ASTEP project aims at detecting and characterizing transiting planets from Dome C, Antarctica, and qualifying this site for photometry in the visible. The first phase of the project, ASTEP South, is a fixed 10 cm diameter instrument pointing continuously towards the celestial South pole. Observations were made almost continuously during 4 winters, from 2008 to 2011. The point-to-point RMS of 1-day photometric lightcurves can be explained by a combination of expected statistical noises, dominated by the photon noise up to magnitude 14. This RMS is large, from 2.5 mmag at R=8 to 6% at R=14, because of the small size of ASTEP South and the short exposure time (30 s). Statistical noises should be considerably reduced using the large amount of collected data. A 9.9-day period eclipsing binary is detected, with a magnitude R=9.85. The 2-season lightcurve folded in phase and binned into 1000 points has a RMS of 1.09 mmag, for an expected photon noise of 0.29 mmag. The use of the 4 seasons of data with a better detrending algorithm should yield a sub-millimagnitude precision for this folded lightcurve. Radial velocity follow-up observations are conducted and reveal a F-M binary system. The detection of this 9.9-day period system with a small instrument such as ASTEP South and the precision of the folded lightcurve show the quality of Dome C for continuous photometric observations, and its potential for the detection of planets with orbital period longer than those usually detected from the ground.


Proceedings of SPIE | 2012

Preliminary optical design for the WEAVE two-degree prime focus corrector

Tibor Agócs; Don Carlos Abrams; Diego Cano Infantes; Neil O'Mahony; Kevin Dee; Jean Baptiste Daban; Carole Gouvret; S. Ottogalli

We present the preliminary optical design for a new two-degree refractive prime focus corrector for the 4.2m William Herschel Telescope optimised for the wide-field multi-object spectrograph, WEAVE (WHT Enhanced Area Velocity Explorer). From the two conceptual designs described previously [1], the counter-rotating atmospheric dispersion corrector approach was selected and further optimized to meet the flat image surface requirement. The preliminary design provides good polychromatic image quality. The PSF does not exceed 0.6 arcsec (80% encircled energy) over a wavelength range from 370 to 1000nm covering a two degree FOV for zenith angles up to 65 degrees. We describe the correctors performance and the trade-off between telecentricity and the requirement for a flat image surface. We present the results of the tolerance and thermal analyses, ghost and scattered light calculations and the finite element analysis that are necessary to establish the PSF error budget for the corrector.


Ground-based and Airborne Telescopes VII | 2018

An end-to-end Fresnel propagation model for SPEED: PIAACMC implementation and performance

Mathilde Beaulieu; Lyu Abe; Olivier Guyon; Carole Gouvret; Oliver Preis; Julien Dejonghe; Patrice Martinez

Future extremely large telescopes, equipped with high-contrast instruments targeting very small Inner Working Angle, will provide the requisite resolution for detecting exoplanets in the habitable zone around M-stars. However, the ELT segmented pupil shape is unfavourable to high-contrast imaging. In this context, the SPEED project aims to develop and test solutions for high contrast with unfriendly apertures. SPEED will combine a PIAACMC coronagraph and two deformable mirrors for the wavefront shaping. In this paper, we describe an end-to-end model of SPEED, including the Fresnel wavefront propagation, the PIAACMC implementation and the dark hole algorithm, and present a statistical analysis of the predicted performance.

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Lyu Abe

University of Nice Sophia Antipolis

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Patrice Martinez

Centre national de la recherche scientifique

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Jean-Baptiste Daban

Centre national de la recherche scientifique

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Yan Fanteï-Caujolle

Centre national de la recherche scientifique

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Tristan Guillot

Centre national de la recherche scientifique

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F. Vakili

Centre national de la recherche scientifique

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F.-X. Schmider

University of Nice Sophia Antipolis

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E. Bondoux

Concordia University Wisconsin

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