On-Sky Operations with the ALES Integral Field Spectrograph

Abstract

The integral field spectrograph configuration of the LMIRCam science camera within the Large Binocular Telescope Interferometer (LBTI) facilitates 2 to 5 $\mu$m spectroscopy of directly imaged gas-giant exoplanets. The mode, dubbed ALES, comprises magnification optics, a lenslet array, and direct-vision prisms, all of which are included within filter wheels in LMIRCam. Our observing approach includes manual adjustments to filter wheel positions to optimize alignment, on/off nodding to track sky-background variations, and wavelength calibration using narrow band filters in series with ALES optics. For planets with separations outside our 1"x1" field of view, we use a three-point nod pattern to visit the primary, secondary and sky. To minimize overheads we select the longest exposure times and nod periods given observing conditions, especially sky brightness and variability. Using this strategy we collected several datasets of low-mass companions to nearby stars.

References in corpus (2)

• The 0.8-14.5 micron Spectra of Mid-L to Mid-T Dwarfs: Diagnostics of Effective Temperature, Grain Sedimentation, Gas Transport, and Surface Gravity
• The LEECH Exoplanet Imaging Survey. Further constraints on the planet architecture of the HR 8799 system

Cited by in corpus (6)

• The HOSTS survey for exozodiacal dust: Observational results from the complete survey
• Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry
• High Contrast Thermal Infrared Spectroscopy with ALES: The 3-4$\mu$m Spectrum of $\kappa$ Andromedae b
• High Spatial Resolution Thermal-Infrared Spectroscopy with ALES: Resolved Spectra of the Benchmark Brown Dwarf Binary HD 130948BC
• Chasing the storm: Investigating the application of high-contrast imaging techniques in producing precise exoplanet light curves
• L-band Integral Field Spectroscopy of the HR 8799 Planetary System