2026/07/06 by Andrea S. J. Lin, Andrea Lin, Ashley Baker +7
Physics and Astronomy · #Astronomy and Astrophysical Research #Atomic and Molecular Physics #Spectroscopy and Quantum Chemical Studies #astro-ph.EP #astro-ph.IM
paper · pdf · doi:10.1117/12.3105370
SPIE Astronomical Telescopes + Instrumentation 2026, paper number 14149-456, submitted to Proc. SPIE
openalex publication_date 2026/07/06 · openalex created_date 2026/07/07 · openalex updated_date 2026/07/14 · arxiv created 2026/07/31 · arxiv updated 2026/08/04
The upcoming HISPEC spectrograph for Keck II will use single-mode fibers fed by the telescope’s adaptive optics system, making it one of a handful of diffraction-limited spectrographs capable of precision radial velocities (PRVs). However, due to the target stars being partially resolved, the resulting RVs are predicted to be affected by differential limb coupling (DLC), where the red- and blue-shifted sides of the stellar disk are coupled unequally into the spectrograph across different epochs, producing an RV error term on the order of several m/s for nearby stars for HISPEC. We present our efforts to directly observe DLC on-sky for the first time with the diffraction-limited spectrograph PARVI in order to verify the expected behavior of DLC and subsequently develop mitigation strategies for HISPEC.