Comparisons of Different Fitting Methods for the Physical Parameters of
  A Star Cluster Sample of M33 with Spectroscopy and Photometry
  Star clusters are good tracers for formation and evolution of galaxies. We
compared different fitting methods by using spectra (or by combining
photometry) to determine the physical parameters. We choose a sample of 17 star
clusters in M33, which previously lacked spectroscopic observations. The
low-resolution spectra were taken with the Xinglong 2.16-m reflector of NAOC.
The photometry used in the fitting includes $\rm u_{SC}$ and $\rm v_{SAGE}$
bands from the SAGE survey, as well as the published $UBVRI$ and $ugriz$
photometry. We firstly derived ages and metallicities with the {\sc ULySS}
(Vazdekis et al. and {\sc pegase-hr}) SSP model and the Bruzual \& Charlot
(2003) (BC03) stellar population synthesis models for the full-spectrum
fitting. The fitting results of both the BC03 and {\sc ULySS} models seem
consistent with those of previous works as well. Then we add the SAGE $\rm
u_{SC}$ and $\rm v_{SAGE}$ photometry in the spectroscopic fitting with the
BC03 models. It seems the results become much better, especially for the Padova
2000+Chabrier IMF set. Finally we add more photometry data, $UBVRI$ and
$ugriz$, in the fitting and we found that the results do not improve
significantly. Therefore, we conclude that the photometry is useful for
improving the fitting results, especially for the blue bands ($\lambda <4000$
{\AA}), e.g., $\rm u_{SC}$ and $\rm v_{SAGE}$ band. At last, we discuss the
"UV-excess" for the star clusters and we find five star clusters have
UV-excess, based on the $GALEX$ FUV, NUV photometry.
