Vol 9, No 9 (2009) / Fan

Multicolor photometric study of M31 globular clusters

Zhou Fan, Jun Ma, Xu Zhou


We present the photometry of 30 globular clusters (GCs) and GC candidates in 15 intermediate-band filters covering the wavelength region from ∼ 3000 to ∼ 10 000 Å using the archival CCD images of M31 observed as part of the Beijing - Arizona - Taiwan - Connecticut (BATC) Multicolor Sky Survey. We transform these intermediate-band photometric data into the photometry in the standard UBV RI broadbands. These M31 GC candidates are selected from the Revised Bologna Catalog (RBC V.3.5), and most of these candidates do not have any photometric data. Therefore, the presented photometric data are a supplement to the RBC V.3.5. We find that 4 out of 61 GCs and GC candidates in RBC V.3.5 do not show any signal on the BATC images at their locations. By applying a linear fit of the distribution in the color-magnitude diagram of blue GCs and GC candidates using data from the RBC V.3.5, in this study, we find the “blue-tilt” of blue M31 GCs with a high confidence at 99.95% or 3.47σ for the confirmed GCs, and > 99.99% or 4.87σ for GCs and GC candidates.


galaxies: individual (M31)— galaxies: star clusters— galaxies: evolution

Full Text:



  • There are currently no refbacks.