摘要：Context.The firstGaiadata release unlocked the access to photometric information for 1.1 billion sources in theG-band. Yet, given the high level of degeneracy between extinction and spectral energy distribution for large passbands such as theGaia G-band, a correction for the interstellar reddening is needed in order to exploitGaiadata.Aims.The purpose of this manuscript is to provide the empirical estimation of theGaiaG-band extinction coefficient kGfor both the red giants and main sequence stars in order to be able to exploit the first data release DR1.Methods.We selected two samples of single stars: one for the red giants and one for the main sequence. Both samples are the result of a cross-match betweenGaiaDR1 and 2MASS catalogues; they consist of high-quality photometry in theG-,J- andKS-bands. These samples were complemented by temperature and metallicity information retrieved from APOGEE DR13 and LAMOST DR2 surveys, respectively. We implemented a Markov chain Monte Carlo method where we used (G–KS)0versusTeffand (J–KS)0versus (G–KS)0, calibration relations to estimate the extinction coefficient kGand we quantify its corresponding confidence interval via bootstrap resampling. We tested our method on samples of red giants and main sequence stars, finding consistent solutions.Results.We present here the determination of theGaiaextinction coefficient through a completely empirical method. Furthermore we provide the scientific community with a formula for measuring the extinction coefficient as a function of stellar effective temperature, the intrinsic colour (G–KS)0, and absorption.
关键词：Key wordsenmethods: data analysismethods: statisticaltechniques: photometricdust, extinctionstars: fundamental parameters
