The SAGE photometric survey: technical description

Abstract

To investigate a huge sample of data related to the Stellar Abundance and Galactic Evolution (SAGE) survey in more detail, we are performing a northern sky photometric survey named SAGES with the SAGE photometric system. This system consists of eight filters: Strӧmgren-u, SAGE-v, SDSS g, r, i, DDO-51, Hα _wide and Hα _narrow, including three Sloan broadband filters, three intermediate-band filters, two narrow-band filters and one newly-designed narrow-band filter. SAGES covers ∼12 000 square degrees of the northern sky with δ > -5°, excluding the Galactic disk (|b| < 10°) and the sky area 12 h < RA < 18 h. The photometric detection limit depth at signal-to-noise ratio 5σ can be as deep as V∼20 mag. SAGES will produce a photometric catalog with uniform depth for ∼500 million stars with atmospheric parameters including effective temperature T _eff, surface gravity log g and metallicity [Fe/H], as well as interstellar extinction to each individual target. In this work, we will briefly introduce the SAGE photometric system, the SAGE survey and a preliminary test field of the open cluster NGC 6791 and its surroundings.