Gemini Planet Imager Observational Calibrations IV: Wavelength Calibration and Flexure Correction for the Integral Field Spectrograph

Abstract

We present the wavelength calibration for the lenslet-based Integral Field Spectrograph (IFS) that serves as the science instrument for the Gemini Planet Imager (GPI). The GPI IFS features a 2.7" x 2.7" field of view and a 190 x 190 lenslet array (14.3 mas/lenslet) operating in $Y$, $J$, $H$, and $K$ bands with spectral resolving power ranging from $R$ $\sim$ 35 to 78. Due to variations across the field of view, a unique wavelength solution is determined for each lenslet characterized by a two-dimensional position, the spectral dispersion, and the rotation of the spectrum with respect to the detector axes. The four free parameters are fit using a constrained Levenberg-Marquardt least-squares minimization algorithm, which compares an individual lenslet's arc lamp spectrum to a simulated arc lamp spectrum. This method enables measurement of spectral positions to better than 1/10th of a pixel on the GPI IFS detector using Gemini's facility calibration lamp unit GCAL, improving spectral extraction accuracy compared to earlier approaches. Using such wavelength calibrations we have measured how internal flexure of the spectrograph with changing zenith angle shifts spectra on the detector. We describe the methods used to compensate for these shifts when assembling datacubes from on-sky observations using GPI.

arXiv comment12 pages, 8 figures. Proceedings of the SPIE, 9147-279

References in corpus (3)

• The Gemini Planet Imager: First Light
• Experimental Design for the Gemini Planet Imager
• The Integral Field Spectrograph for the Gemini Planet Imager

Cited by in corpus (24)

• Improving and Assessing Planet Sensitivity of the GPI Exoplanet Survey with a Forward Model Matched Filter
• Complex Spiral Structure in the HD 100546 Transitional Disk as Revealed by GPI and MagAO
• The Orbit and Transit Prospects for $\beta$ Pictoris b constrained with One Milliarcsecond Astrometry
• An M-dwarf star in the transition disk of Herbig HD 142527; Physical parameters and orbital elements
• Spectroscopic characterization of HD 95086 b with the Gemini Planet Imager
• An Optical/near-infrared investigation of HD 100546 b with the Gemini Planet Imager and MagAO
• Astrometric Confirmation and Preliminary Orbital Parameters of the Young Exoplanet 51 Eridani b with the Gemini Planet Imager
• GPI spectra of HR 8799 c, d, and e from 1.5 to 2.4$\mu$m with KLIP Forward Modeling
• First Scattered-Light Image of the Debris Disk around HD 131835 with the Gemini Planet Imager
• The Gemini Planet Imager Exoplanet Survey: Dynamical Mass of the Exoplanet beta Pictoris b from Combined Direct Imaging and Astrometry
• Gemini Planet Imager Observations of the AU Microscopii Debris Disk: Asymmetries within One Arcsecond
• Evidence that the Directly-Imaged Planet HD 131399 Ab is a Background Star
• The Peculiar Debris Disk of HD 111520 as Resolved by the Gemini Planet Imager
• Constraints on the architecture of the HD 95086 planetary system with the Gemini Planet Imager
• The PDS 66 Circumstellar Disk as seen in Polarized Light with the Gemini Planet Imager
• GPI Spectroscopy of the Mass, Age, and Metallicity Benchmark Brown Dwarf HD 4747 B
• Gemini Planet Imager Spectroscopy of the Dusty Substellar Companion HD 206893 B
• Automated data processing architecture for the Gemini Planet Imager Exoplanet Survey
• Integral Field Spectroscopy of the Low-Mass Companion HD984B with the Gemini Planet Imager
• Gemini Planet Imager Observational Calibrations II: Detector Performance and Calibration
• Gemini Planet Imager Observational Calibrations III: Empirical Measurement Methods and Applications of High-Resolution Microlens PSFs
• Performance of the Gemini Planet Imager Non-Redundant Mask and spectroscopy of two close-separation binaries HR 2690 and HD 142527
• HD 165054: an astrometric calibration field for high-contrast imagers in Baade's Window
• A Multi-Wavelength Study of the Highly Asymmetrical Debris Disk Around HD 111520