Jean-Francois Lavigne

Gemini Planet Imager observational calibrations I: Overview of the GPI data reduction pipeline

The Gemini Planet Imager (GPI) has as its science instrument an infrared integral field spectrograph/polarimeter (IFS). Integral field spectrographs are scientificially powerful but require sophisticated data reduction systems. For GPI to achieve its scientific goals of exoplanet and disk characterization, IFS data must be reconstructed into high quality astrometrically and photometrically accurate datacubes in both spectral and polarization modes, via flexible software that is usable by the broad Gemini community. The data reduction pipeline developed by the GPI instrument team to meet these needs is now publicly available following GPI’s commissioning. This paper, the first of a series, provides a broad overview of GPI data reduction, summarizes key steps, and presents the overall software framework and implementation. Subsequent papers describe in more detail the algorithms necessary for calibrating GPI data. The GPI data reduction pipeline is open source, available from planetimager.org, and will continue to be enhanced throughout the life of the instrument. It implements an extensive suite of task primitives that can be assembled into reduction recipes to produce calibrated datasets ready for scientific analysis. Angular, spectral, and polarimetric differential imaging are supported. Graphical tools automate the production and editing of recipes, an integrated calibration database manages reference files, and an interactive data viewer customized for high contrast imaging allows for exploration and manipulation of data.

Extreme Adaptive Optics for the Thirty Meter Telescope

Direct detection of extrasolar Jovian planets is a major scientific motivation for the construction of future extremely large telescopes such as the Thirty Meter Telescope (TMT). Such detection will require dedicated high-contrast AO systems. Since the properties of Jovian planets and their parent stars vary enormously between different populations, the instrument must be designed to meet specific scientific needs rather than a simple metric such as maximum Strehl ratio. We present a design for such an instrument, the Planet Formation Imager (PFI) for TMT. It has four key science missions. The first is the study of newly-formed planets on 5-10 AU scales in regions such as Taurus and Ophiucus - this requires very small inner working distances that are only possible with a 30m or larger telescope. The second is a robust census of extrasolar giant planets orbiting mature nearby stars. The third is detailed spectral characterization of the brightest extrasolar planets. The final targets are circumstellar dust disks, including Zodiacal light analogs in the inner parts of other solar systems. To achieve these, PFI combines advanced wavefront sensors, high-order MEMS deformable mirrors, a coronagraph optimized for a finely- segmented primary mirror, and an integral field spectrograph.

Data reduction pipeline for the Gemini Planet Imager

The Gemini Planet Imager (GPI) high-contrast adaptive optics system, which is currently under construction for Gemini South, has an IFS as its science instrument. This paper describes the data reduction pipeline of the GPI science instrument. Written in IDL, with a modular architecture, this pipeline reduces an ensemble of highcontrast spectroscopic or polarimetric raw science images and calibration data into a final dataset ready for scientific analysis. It includes speckle suppression techniques such as angular and spectral differential imaging that are necessary to achieve extreme contrast performances for which the instrument is designed. This paper presents also raw GPI IFS simulated data developed to test the pipeline.

NEAR-INFRARED OBSERVATIONS OF GQ LUP b USING THE GEMINI INTEGRAL FIELD SPECTROGRAPH NIFS

We present new JHK spectroscopy (R ~ 5000) of GQ Lup b, acquired with the Near-Infrared Integral Field Spectrograph and the adaptive optics system ALTAIR at the Gemini North telescope. Angular differential imaging was used in the J and H bands to suppress the speckle noise from GQ Lup A; we show that this approach can provide improvements in signal-to-noise ratio (S/N) by a factor of 2-6 for companions located at subarcsecond separations. Based on high-quality observations and Global Astrometric lnterferometer for Astrophysics synthetic spectra, we estimate the companion effective temperature to T eff = 2400 ± 100 K, its gravity to log g = 4.0 ± 0.5, and its luminosity to log(L/L ☉) = –2.47 ± 0.28. Comparisons with the predictions of the DUSTY evolutionary tracks allow us to constrain the mass of GQ Lup b to 8-60 M Jup, most likely in the brown dwarf regime. Compared with the spectra published by Seifahrt and collaborators, our spectra of GQ Lup b are significantly redder (by 15%-50%) and do not show important Paβ emission. Our spectra are in excellent agreement with the lower S/N spectra previously published by McElwain and collaborators.

GPI: cryogenic spectrograph optics performances

The science instrument for GPI (Gemini Planet Imager) is a cryogenic integral field spectrograph based on a lenslet array. The integral field nature of the instrument allows for a full mapping of the focal plane at coarse spectral resolution. With such a data cube, artifacts within the PSF such as residual speckles can be suppressed. Additionally, the initial detection of any candidate planet will include spectral information that can be used to distinguish it from a background object: candidates can be followed up with detailed spectroscopic observations. The optics between the lenslet array and the detector are essentially a standard spectrograph with a collimating set of lenses, a dispersive prism and a camera set of lenses in a folded assembly. We generally refer to this optical set as the spectrograph optics. This paper describes the laboratory optical performances over the field of view. The test procedure includes the imaging performances in both non dispersive and dispersive mode. The test support equipments include a test cryostat, an illumination module with monochromatic fiber laser, a wideband light source and a test detector module.

Woofer - Tweeter Control Algorithm for the Gemini Planet Imager

The Gemini Planet Imager requires two deformable mirrors: the woofer and the tweeter. This paper shows that command splitting computational efficiency greatly improves if moved from the tweeter command space to the Fourier domain.

Study of the image quality and stray light in the critical design phase of the Compact Echelle Spectrograph for Aeronomical Research (CESAR)

The success of the high resolution nightglow studies conducted with the Keck telescopes on Mauna Kea and the Very Large Telescopes in Chile led to the design of the Compact Echelle Spectrograph for Aeronomical Research (CESAR). This is an echelle spectrograph with grating post-dispersion that will be dedicated to nightglow studies at high spectral resolution (R ~ 20000) between 300-1000 nm, and that will be easily deployable at different sites. The development of CESAR is conducted by SRI International, and INO is involved in the optical design and integration of the spectrograph camera, whose all-spherical form is based on the camera of the HIRES spectrograph at the Keck I telescope. The detailed optical design is used to calculate the position of the spectral elements on the detector, predict their image quality, and estimate the level of stray light. This paper presents the methodology used in these analyses.

Optical performance results for the polar communication and weather mission space technology development program

Current fleet of geostationary Earth orbit (GEO) satellites are used to provide communication in remote areas and to acquire meteorological data that are fed to Numerical Weather Predictions models.

HVRM: a second generation ACE-FTS instrument concept

The Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) is the main instrument on-board the SCISAT-1 satellite, a mission mainly supported by the Canadian Space Agency [1]. It is in Low- Earth Orbit at an altitude of 650 km with an inclination of 74E. Its data has been used to track the vertical profile of more than 30 atmospheric species in the high troposphere and in the stratosphere with the main goal of providing crucial information for the comprehension of chemical and physical processes controlling the ozone life cycle. These atmospheric species are detected using high-resolution (0.02 cm-1) spectra in the 750-4400 cm-1 spectral region. This leads to more than 170 000 spectral channels being acquired in the IR every two seconds. It also measures aerosols and clouds to reduce the uncertainty in their effects on the global energy balance. It is currently the only instrument providing such in-orbit high resolution measurements of the atmospheric chemistry and is often used by international scientists as a unique data set for climate understanding. The satellite is in operation since 2003, exceeding its initially planned lifetime of 2 years by more than a factor of 5. Given its success, its usefulness and the uniqueness of the data it provides, the Canadian Space Agency has founded the development of technologies enabling the second generation of ACE-FTS instruments through the High Vertical Resolution Measurement (HVRM) project but is still waiting for the funding for a mission. This project addresses three major improvements over the ACE-FTS. The first one aims at improving the vertical instantaneous field-of-view (iFoV) from 4.0 km to 1.5 km without affecting the SNR and temporal precision. The second aims at providing precise knowledge on the tangent height of the limb observation from an external method instead of that used in SCISAT-1 where the altitude is typically inferred from the monotonic CO2 concentration seen in the spectra. The last item pertains to reaching lower altitude down to 5 km for the retrieved gas species, an altitude at which the spectra are very crowded in terms of absorption. These objectives are attained through a series of modification in the optical train such as the inclusion of a field converter and a series of dedicated real-time and post-acquisition algorithms processing the Sun images as it hides behind the Earth. This paper presents the concepts, the prototypes that were made, their tests and the results obtained in this Technology Readiness Level (TRL) improvement project.

Canadian contributions studies for the WFIRST instruments

WFIRST-AFTA is the NASA’s highest ranked astrophysics mission for the next decade that was identified in the New World, New Horizon survey. The mission scientific drivers correspond to some of the deep questions identified in the Canadian LRP2010, and are also of great interest for the Canadian scientists. Given that there is also a great interest in having an international collaboration in this mission, the Canadian Space Agency awarded two contracts to study a Canadian participation in the mission, one related to each instrument. This paper presents a summary of the technical contributions that were considered for a Canadian contribution to the coronagraph and wide field instruments.