摘要：Combining the precise parallaxes and optical photometry delivered byGaia’s second data release with the photometric catalogues of Pan-STARRS1, 2MASS, and AllWISE, we derived Bayesian stellar parameters, distances, and extinctions for 265 million of the 285 million objects brighter thanG = 18. Because of the wide wavelength range used, our results substantially improve the accuracy and precision of previous extinction and effective temperature estimates. After cleaning our results for both unreliable input and output data, we retain 137 million stars, for which we achieve a median precision of 5% in distance, 0.20 mag inV-band extinction, and 245 K in effective temperature forG ≤ 14, degrading towards fainter magnitudes (12%, 0.20 mag, and 245 K atG = 16; 16%, 0.23 mag, and 260 K atG = 17, respectively). We find a very good agreement with the asteroseismic surface gravities and distances of 7000 stars in theKepler, K2-C3, and K2-C6 fields, with stellar parameters from the APOGEE survey, and with distances to star clusters. Our results are available through the ADQL query interface of theGaiamirror at the Leibniz-Institut für Astrophysik Potsdam (gaia.aip.de) and as binary tables atdata.aip.de. As a first application, we provide distance- and extinction-corrected colour-magnitude diagrams, extinction maps as a function of distance, and extensive density maps. These demonstrate the potential of our value-added dataset for mapping the three-dimensional structure of our Galaxy. In particular, we see a clear manifestation of the Galactic bar in the stellar density distributions, an observation that can almost be considered direct imaging of the Galactic bar.
关键词：enstars: fundamental parametersstars: distancesstars: statisticsdustextinctionGalaxy: stellar contentGalaxy: structure
