A new method for extracting seismic indices and granulation parameters: results for more than 20,000 CoRoT and Kepler red giants

TL;DR

The paper introduces MLEUP, an automated method combining MLE and the Universal Pattern to simultaneously measure seismic and granulation parameters in over 20,000 red giants from CoRoT and Kepler data, providing a large, consistent dataset.

Contribution

It presents a novel automated approach, MLEUP, for consistent measurement of seismic and granulation parameters in red giants, validated with simulations and applied to extensive space data.

Findings

Seismic indices for 20,122 red giants obtained.

Granulation parameters for 17,109 red giants provided.

Method calibrated and corrected for biases and errors.

Abstract

We have developed a new automated method intended to perform the simultaneous - and thus more consistent - measurement of both the seismic indices characterizing the oscillations and the parameters characterizing the granulation signature of red-giant stars. This method, called MLEUP, takes advantage of the Maximum Likelihood Estimate (MLE) algorithm combined with the parametrized representation of red giant pulsation spectra following the Universal Pattern (UP). Its performances have been tested on Monte Carlo simulations for observation conditions representative of CoRoT and Kepler data. These simulations allowed us to determine, calibrate and propose correction for the biases on the parameter estimates as well as on the error estimates produced with MLEUP. Finally, we applied MLEUP to CoRoT and Kepler data. In total, MLEUP yields seismic indices for 20,122 red giant stars and granulation parameters for 17,109 of them. These data have been made available in the Stellar Seismic Indices database (http://ssi.lesia.obspm.fr/).