{
  "id": "2009.05712",
  "version": "v1",
  "published": "2020-09-12T03:15:31.000Z",
  "updated": "2020-09-12T03:15:31.000Z",
  "title": "Comparisons of Different Fitting Methods for the Physical Parameters of A Star Cluster Sample of M33 with Spectroscopy and Photometry",
  "authors": [
    "Zhou Fan",
    "Bingqiu Chen",
    "Xiaoying Pang",
    "Juanjuan Ren",
    "Song Wang",
    "Jing Wang",
    "Kefeng Tan",
    "Nan Song",
    "Chun Li",
    "Jie Zheng",
    "Gang Zhao"
  ],
  "comment": "Accepted for publication in ApJS",
  "categories": [
    "astro-ph.GA",
    "astro-ph.SR"
  ],
  "abstract": "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.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-09-12T03:15:31.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "star cluster sample",
      "photometry",
      "physical parameters",
      "fitting methods",
      "spectroscopy"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}