论文标题
银河球状簇的等铁拟合-II。 NGC6205（M13）
Isochrone fitting of Galactic globular clusters -- II. NGC6205 (M13)
论文作者
论文摘要
我们提出了新的等异弦符合银河球簇NGC \，6205（M13）的颜色磁性图。我们通过使用{\ it HST}，{\ it Gaia} dr2，SDSS，不明智的DR1和其他光度法来源的数据利用34个光度波段从紫外线到中红外。在我们的等异弦拟合中，我们使用Parsec，Mist，DSEP，Basti和IAC-Basti理论模型和等音模型，以及用于太阳尺度和HE-$α$增强丰度，金属性的金属性约为[Fe/H] $ = -1.58 $ = -1.58 $。从不同数据集但相似有效波长的一对过滤器获得的颜色 - 磁性图显示了在基准序列和等距离之间最高0.04 mag的颜色偏移。我们将这些偏移归因于数据集的系统差异。我们的结果中仍然存在一些模型/等级龙的内在系统差异：紫外线，光学和红外光度法的衍生距离和年龄是不同的，而衍生的年龄对于不同的模型/等级龙来说是不同的，例如。在光学范围内，$ 12.3 \ pm0.7 $ gyr for He- $α$添加的DSEP到$ 14.4 \ pm0.7 $ gyr for Mist。 Despite the presence of multiple stellar populations, we obtain convergent estimates for the dominant population: best-fitting distance $7.4\pm0.2$ kpc, true distance modulus $14.35\pm0.06$ mag, parallax $0.135\pm0.004$ mas, extinction $A_\mathrm{V}=0.12\pm0.02$, and reddening $ e（b-v）= 0.04 \ pm0.01 $。这些估计与其他最近的估计相吻合，但是，灭绝和发红的高度是普遍接受的两倍。派生的经验灭绝法与Cardelli-Clayton-Mathis灭绝法具有最合适的$ R_ \ Mathrm {V} = 3.1^{+1.6} _ { - 1.1} $。
We present new isochrone fits to colour-magnitude diagrams of the Galactic globular cluster NGC\,6205 (M13). We utilise 34 photometric bands from the ultraviolet to mid-infrared by use of data from the {\it HST}, {\it Gaia} DR2, SDSS, unWISE, Pan-STARRS DR1, and other photometric sources. In our isochrone fitting we use the PARSEC, MIST, DSEP, BaSTI, and IAC-BaSTI theoretical models and isochrones, both for the solar-scaled and He-$α$-enhanced abundances, with a metallicity of about [Fe/H]$=-1.58$ adopted from the literature. The colour-magnitude diagrams, obtained with pairs of filters from different datasets but of similar effective wavelengths, show some colour offsets up to 0.04 mag between the fiducial sequences and isochrones. We attribute these offsets to systematic differences of the datasets. Some intrinsic systematic differences of the models/isochrones remain in our results: the derived distances and ages are different for the ultraviolet, optical and infrared photometry used, while the derived ages are different for the different models/isochrones, e.g. in the optical range from $12.3\pm0.7$ Gyr for He-$α$-enhanced DSEP to $14.4\pm0.7$ Gyr for MIST. Despite the presence of multiple stellar populations, we obtain convergent estimates for the dominant population: best-fitting distance $7.4\pm0.2$ kpc, true distance modulus $14.35\pm0.06$ mag, parallax $0.135\pm0.004$ mas, extinction $A_\mathrm{V}=0.12\pm0.02$, and reddening $E(B-V)=0.04\pm0.01$. These estimates agree with other recent estimates, however, the extinction and reddening are twice as high as generally accepted. The derived empirical extinction law agrees with the Cardelli-Clayton-Mathis extinction law with the best-fitting $R_\mathrm{V}=3.1^{+1.6}_{-1.1}$.
