Wide-field Survey of Globular Clusters in M31. I. a Catalog of New Clusters

We present the result of a wide-field survey of globular clusters (GCs) in M31 covering a 3 × 3 field centered on M31. We have searched for GCs on CCD images taken with Washington CMT1 filters at the KPNO 0.9 m telescope using the following steps: (1) inspection of morphological parameters given by the SExtractor package such as stellarity, full width at half-maximum, and ellipticity; (2) consulting the spectral types and radial velocities obtained from spectra taken with the Hydra spectrograph at the WIYN 3.5 m telescope; and (3) visual inspection of the images of each object. We have found 1164 GCs and GC candidates, of which 605 are newly found GCs and GC candidates and 559 are previously known GCs. Among the new objects there are 113 genuine GCs, 258 probable GCs, and 234 possible GCs, according to our classification criteria. Among the known objects there are 383 genuine GCs, 109 probable GCs, and 67 possible GCs. In total there are 496 genuine GCs, 367 probable GCs and 301 possible GCs. Most of these newly found GCs have T1 magnitudes of 17.5 − 19.5 mag, [17.9 <V < 19.9 mag assuming (C − T1) ≈ 1.5], and (C − T1) colors in the range 1 − 2. Subject headings: galaxies: star clusters — galaxies: spiral — galaxies: individual (M31, NGC 224) — Local Group