Title: PSF characterization and correction in high-resolution spectra
Speaker: Maddalena Bugatti (University of Geneva)
Abstract:
To detect Earth-like planets, radial velocities must be measured to a precision of cm/s. At that level, variations in the spectrograph's point-spread function (PSF) can affect the measured stellar Doppler shifts. The PSF is asymmetric, changes across the detector, and drifts over time. Standard pipelines do not account for any of this. I will present a method that measures the PSF of HARPS, the high-precision spectrograph on the ESO 3.6m telescope at La Silla, Chile, using laser frequency comb spectra. The method then removes the PSF from stellar spectra. I will then show what this correction does to radial velocity measurements for a sample of stars, and what it could mean for other
instruments.
