Point Spread Function Modelling and Spectro-perfectionism for Radial Velocity Spectrographs
Abstract
In the search for earth-like exoplanets, multiple radial velocity echelle spectrographs calibrated by ultra-precise laser frequency combs (LFCs) are being commissioned, enabling novel methods in the extraction of high-resolution spectra. Spectro-perfectionism, first devised by Adam Bolton and David Schlegel for the Sloan Digital Sky Survey spectrograph, incorporates information about the instrument's point spread function (PSF) to increase the signal-to-noise of the data and extract spectra above the diffraction-limited resolution of the spectrograph. We implement a similar technique in the extraction pipeline of the Extreme Precision Spectrograph (EXPRES) and compare it to the current standard, optimal extraction. To accurately measure the PSF of EXPRES, we have built a 500 GHz LFC, based on an aluminum nitride resonating waveguide developed by the Yale Nanodevices Lab. This device allows us to parameterize the two-dimensional analytic form of our instrument's PSF across the entire spectral range of the echellogram. We then apply this PSF to a Gold deconvolution algorithm that deconvolves the image to the sampling limit of the detector. Current results have shown a significant increase in both signal-to-noise and resolution for LFC and stellar spectra taken by EXPRES.
- Publication:
-
American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019
- Bibcode:
- 2019AAS...23322501P