Spectral energy distributions of M81 globular clusters in the BATC Multicolor Survey

摘要

In this paper, we give the spectral energy distributions (SEDs) of 42 M81 globular clusters in 13 intermediate-band filters from 4000 to 10000 angstrom using the CCD images of M81, observed as part of the Beijing-Arizona-Taiwan-Connecticut (BATC) Multicolor Sky Survey. The BATC multicolor filter system is specifically designed to exclude most of the bright and variable night-sky emission lines, including the OH forest. Hence, it can present accurate SEDs of the observed objects. These SEDs are low-resolution spectra and can reflect the stellar populations of the globular clusters. This paper confirms the conclusions of Schroder et al., that M81 contains clusters as young as a few Gyr, which were also observed in both M31 and M33.