RMC-001 - Gaia
Summary: This technical note describes the process followed to generate the catalogues BGMBTG 2.08 and 2.012 to be used in the CU9-WP943 to validate Gaia data. For that, the Czekaj et al. (2014) version of the Besançon Galaxy Model (BGM) has been used. These samples are limited in apparent G magnitude up to G=13 and contain both single stars and multiple systems. The simulated catalogues include true (not affected by errors) astrometric and photometric data as well as ”observable” data obtained assuming that stars are affected by Tycho errors (Høg et al. 2000), TGAS errors (Michalik et al. 2015), and 6 month Gaia data errors (following the recipes published in September 2014 on the Gaia performance webpage). A first comparison between model and Tycho-2 data up to V=11 is presented and discussed. Star counts maps show a general good agreement but in the Galactic plane, where Marshall’s extinction seems not adequate for short distances (1-2 kpc). Proper motions map reflect a shift probably due to the adopted solar motion and mean motion of the LSR.
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