Image Details
Caption: Figure 2.
The BDBS differentially dereddened CMD for i0 versus (u − i)0 is shown. The small, gray-filled circles are the stars within 1﹩\mathop{.}\limits^{^{\prime} }﹩2 of the center of NGC 6569. The following objects are identified within 5 tidal radii of the center of the cluster: stars within 0﹩\mathop{.}\limits^{\unicode{x000b0}}﹩95 of the cluster center; stars must have a PM within 1 mas yr−1 in R.A. and within 1.5 mas yr−1 in decl. of the main cluster PM: a box drawn between (∼–4.125 ± 1.0 mas yr−1, ∼–7.354 ± 1.5 mas yr−1). Additional constraints were applied: objects with BDBS u magnitudes with uncertainties <0.04 mag. were selected if they had detections in the BDBS g and i bands also. The red open squares were identified as targets for AAT/AAOmega spectroscopy. Blue triangles are flagged as likely foreground objects, and black-filled squares are identified as RRLs. The isochrone shown is from the MIST models (J. Choi et al. 2016), [Fe/H] = –0.75 dex, scaled for [α/Fe] = +0.3 dex external to MIST, with an age of 13 Gyr.
© 2026. The Author(s). Published by the American Astronomical Society.