A Swiss Watch Running on Chilean Time: A Progress Report on Two New Automated CORALIE RV Pipelines

TL;DR

This paper reports on the development of two independent, fully automated pipelines for processing CORALIE spectrograph data, achieving stable radial velocity measurements and aiming for improved precision and broader instrument application.

Contribution

The paper introduces two new automated pipelines for CORALIE data analysis, implemented in IDL and Python, with initial stability of 12-15 m/s and plans for further improvements.

Findings

Achieved long-term stability of 12-15 m/s in radial velocity measurements.

Developed pipelines capable of full automation from raw data to velocity extraction.

Plans to improve stability to 5-6 m/s and adapt pipelines to other instruments like HARPS.

Abstract

We present the current status of two new fully automated reduction and analysis pipelines, built for the Euler telescope and the CORALIE spectrograph. Both pipelines have been designed and built independently at the Universidad de Chile and Universidad Catolica by the two authors. Each pipeline has also been written on two different platforms, IDL and Python, and both can run fully automatically through full reduction and analysis of CORALIE datasets. The reduction goes through all standard steps from bias subtraction, flat-fielding, scattered light removal, optimal extraction and full wavelength calibration of the data using well exposed ThAr arc lamps. The reduced data are then cross-correlated with a binary template matched to the spectral type of each star and the cross-correlation functions are fit with a Gaussian to extract precision radial-velocities. For error analysis we are currently testing bootstrap, jackknifing and cross validation methods to properly determine uncertainties directly from the data. Our pipelines currently show long term stability at the 12-15m/s level, measured by observations of two known radial-velocity standard stars. In the near future we plan to get the stability down to the 5-6m/s level and also transfer these pipelines to other instruments like HARPS.