2007/11/30 by Z. Fan, Jun Ma, J. Ma +5 · 5 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astronomy #Astrophysics #Atmospheric Ozone and Climate #Cluster (spacecraft) #Galaxy #Globular cluster #Horizontal branch #Luminosity #Metallicity #Physics #RADIUS #Solar and Space Plasma Dynamics #Star cluster #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2007.12790.x
Accepted for Publication in MNRAS, 18 pages, 13 figures
arxiv created 2007/11/30 · openalex publication_date 2008/03/19 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Using metallicities from the literature, combined with the Revised Bologna Catalogue of photometric data for M31 clusters and cluster candidates (the latter of which is the most comprehensive catalogue of M31 clusters currently available, including 337 confirmed globular clusters -GCs -and 688 GC candidates), we determine 443 reddening values and intrinsic colours, and 209 metallicities for individual clusters without spectroscopic observations. This, the largest sample of M31 GCs presently available, is then used to analyse the metallicity distribution of M31 GCs, which is bimodal with peaks at [Fe/H] -1.7 and -0.7 dex. An exploration of metallicities as a function of radius from the M31 centre shows a metallicity gradient for the metal-poor GCs, but no such gradient for the metal-rich GCs. Our results show that the metal-rich clusters appear as a centrally concentrated spatial distribution; however, the metal-poor clusters tend to be less spatially concentrated. There is no correlation between luminosity and metallicity among the M31 sample clusters, which indicates that self-enrichment is indeed unimportant for cluster formation in M31. The reddening distribution shows that slightly more than half of the GCs are affected by a reddening of E(B -V ) 0.2 mag; the mean reddening value is E(B -V ) = 0.28 +0.23 -0.14 mag. The spatial distribution of the reddening values indicates that the reddening on the northwestern side of the M31 disc is more significant than that on the southeastern side, which is consistent with the conclusion that the northwestern side in nearer to us.