MWM is targeting OB stars using their high luminosities and blue intrinsic colors. The main sample selection is done in the spirit of the SDSS-V requirement of a known and well-defined selection function, and is therefore based on Gaia DR2 photometry and astrometry combined with the 2MASS photometric information. First, all objects whose absolute magnitude in the K photometric band is smaller than -0.61 are selected, which roughly corresponds to a B3 main-sequence star. Ultimately, several color cuts are applied to clean the sample from intrinsically bright red giant- and asymptotic giant-branch stars, as well as from objects with unnaturally blue colors. The target selection and its rationale is described more fully in Zari et al. (2021). In addition, a few thousand Cepheids from the catalog of Inno et al. (2021).
OB Star Cartons in Targeting Generation v0.5.3
- parallax < 10((10-K-0.61)/5)
- G < 16
- J-K-0.25(G-K) < 0.10
- J-K-0.25(G-K)> -0.30
- J-H > 0.15(G-K)-0.15
- J-K < 0.23(G-K)+0.03
- G > 2(G-K)+3.0
- Cross-match separation between Gaia DR2 and 2MASS < 1″
- ruwe < 1.4
- In Inno et al. (2021) catalog
All OB star program cartons take the bright_3x1 cadence.