HARPS Legacy Data Release: Fully Reprocessed Spectra and Radial Velocities from Archival Observations

The high-resolution spectrograph HARPS, installed at ESO La Silly Observatory, Chile, is one of the most precise high-resolution spectrographs currently in operation. In the field of exoplanets, it plays a key role in the detection of low-amplitude exoplanets, in Rossiter–McLaughlin effect measurements, and in atmospheric transit spectroscopy.

As part of a comprehensive effort led by the Geneva Exoplanet Team with support from the DACE platform, HARPS public data were retrieved from the ESO archive and fully curated. This curation includes target identification, homogenization of coordinates, proper motions, mean radial velocities, and stellar spectral types, using Gaia DR3 as a reference.

All spectra were then uniformly reprocessed using the latest version of the HARPS Data Reduction Software (DRS v3.3.6), and the resulting data products are now available through the Open Data module of the DACE platform.

The HARPS Legacy Data Release includes 303’521 high-resolution spectra of 6’802 individual targets, observed from June 2003 to December 2022. It comprises calibrated 2D echelle spectra (E2DS) and their corresponding 2D cross-correlation functions (CCFs), from which radial velocity time series are derived. Reconstructed individual 1D spectra (S1D) are also provided as part of the standard ESPRESSO-DRS output.

This release aims to support a broad range of exoplanetary and stellar studies and to serve as a legacy resource for the astronomical research community.

The Data Analysis Center for Exoplanets (DACE) is a platform of the Swiss National Centre of Competence in Research (NCCR) PlanetS, which federates Swiss expertise in exoplanet research. It is supported by the Swiss National Science Foundation under grants 51NF40_182901 and 51NF40_205606, and is based at the Department of Astronomy of the University of Geneva, Switzerland.