论文标题
从深HST/ACS光度法中对hydra i的凸状星系中的球状簇的研究
A study of globular clusters in a lenticular galaxy in Hydra I from deep HST/ACS photometry
论文作者
论文摘要
我们利用来自F475W（$ G_ {F475W} $）和F606W（$ v_ {f606W} $）频段中HST/ACS的精美深度光学成像数据，以研究中间质量列中列中列中的球形集群（GC）的属性。我们检查了位于PGC 087327的$ \ sim19 \ times19 $ kpc面积的源的光度（幅度和颜色）和形态计量学（紧凑，伸长等）的性能，并将它们与相同的HST/ACS MOSAIC上的四个相邻领域进行比较。这使我们能够确定GC候选者的列表，并使用背景净化方法检查其属性。相对于四个比较字段，PGC 087327显示了GCS强大密度，$ n_ {gc} = 82 \ pm9 $。按照银河系的估计幅度，该数字意味着$ s_n = 1.8 \ pm0.7 $的特定频率。尽管有$ g_ {f475w} $和$ v_ {f606w} $ passbands的短波长间隔，但颜色分布显示出明显的双峰性，蓝色峰为$ \ langle g_ {f475w} $ \ langle g_ {f475w} { - } v_ {f606w} \ rangle = 0.62 \ pm0.03 $ mag。我们还观察到红色GC相对于蓝色GC的径向分布的典型陡峭斜率。由于可用数据的独特深度，我们表征了GC光度函数（GCLF），远远超出了预期的GCLF转换。我们发现$ g^{tom} _ {f475w} = 26.54 \ pm0.10 $ mag和$ v^{tom} _ {f606w} = 26.08 \ pm 0.09 $ mag，校准后，校准后会产生$ d_ {gclf} = 56.7 $ pm 4.3（pm 4.3（pm）。
We take advantage of exquisitely deep optical imaging data from HST/ACS in the F475W ($g_{F475W}$) and F606W ($V_{F606W}$) bands, to study the properties of the globular cluster (GC) population in the intermediate mass lenticular galaxy PGC 087327, in the Hydra I galaxy cluster. We inspect the photometric (magnitudes and color) and morphometric (compactness, elongation, etc.) properties of sources lying in an area of $\sim19\times19$ kpc centered on PGC 087327, and compare them with four neighbouring fields over the same HST/ACS mosaic. This allowed us to identify a list of GC candidates and to inspect their properties using a background decontamination method. Relative to the four comparison fields, PGC 087327 shows a robust overdensity of GCs, $N_{GC}=82\pm9$. At the estimated magnitude of the galaxy, this number implies a specific frequency of $S_N=1.8\pm0.7$. In spite of the short wavelength interval available with the $g_{F475W}$ and $V_{F606W}$ passbands, the color distribution shows a clear bimodality with a blue peak at $\langle g_{F475W}{-}V_{F606W} \rangle =0.47\pm0.05$ mag and a red peak at $\langle g_{F475W}{-}V_{F606W}\rangle =0.62\pm0.03$ mag. We also observe the typical steeper slope of the radial distribution of red GCs relative to blue ones. Thanks to the unique depth of the available data, we characterize the GC luminosity function (GCLF) well beyond the expected GCLF turn-over. We find $g^{TOM}_{F475W} = 26.54\pm0.10$ mag and $V^{TOM}_{F606W} = 26.08 \pm 0.09$ mag, which after calibration yields a distance of $D_{GCLF} = 56.7 \pm 4.3(statistical) \pm 5.2(systematic)$ Mpc.
