论文标题
VVVX-GAIA在银河系磁盘中发现低亮度球形集群
VVVX-Gaia Discovery of a Low Luminosity Globular Cluster in the Milky Way Disk
论文作者
论文摘要
银河系球状簇（MW GC）由于高差分灭绝和沉重的恒星拥挤而难以在低银河纬度上识别。来自ViaLáctea扩展调查（VVVX）中Vista变量的新的深近IR图像和光度法使我们能够绘制先前未开发的区域。我们的长期目标是完成MW GC的普查。直接的目标是估计天体物理参数，测量其红色，灭绝，距离，总发光性，适当的运动，大小，金属性和年龄。我们将近IIR VVVX调查数据库与Gaia DR2光学光度法结合使用，并与两个Micron All Sky Survey（2 Mass）光度法结合使用。我们报告了迄今未知的银河球形集群的检测$ ra = $ 14：09：00.0； $ dec = - $ 65：37:12（J2000）。我们计算出$ e（j-k_s）=（0.3 \ pm 0.03）$ mag和$ a_ {k_s} =（0.15 \ pm 0.01）$ mag的红色（0.3 \ pm 0.03）。其距离模量和相应的距离分别测量为$（M-M）=（15.93 \ pm0.03）$ mag和$ d =（15.5 \ pm1.0）$ kpc。我们通过与已知的GCS以及安装PARSEC和DARTMOUTH等速线相比，估计金属性和年龄，找到$ [Fe/h] =（ - 0.70 \ pm0.2）$ dex和$ t =（11.0 \ pm1.0）$ gyr。 GAIA的平均GC PM为$μ_{α^\ ast} =（ - 4.68 \ pm 0.47）$ mas $ yr $ yr^{ - 1} $和$μ_Δ=（ - 1.34 \ pm 0.45）$ yr $ yr $ yr^{ - 1} $。我们集群的总发光度估计为$ M_ {ks} =（ - 7.76 \ pm 0.5）$ mag。我们发现了一种新的低亮度，旧且金属丰富的球状簇位于银河磁盘的另一侧，$ r_ {g} = 11.2 $ kpc，来自银河系中心，$ z = 1.0 $ kpc = 1.0 $ kpc。有趣的是，该球状簇的位置，金属性和年龄与Monoceros环（MRI）结构一致。
Milky Way globular clusters (MW GCs) are difficult to identify at low Galactic latitudes because of high differential extinction and heavy star crowding. The new deep near-IR images and photometry from the VISTA Variables in the Via Láctea Extended Survey (VVVX) allow us to chart previously unexplored regions. Our long term aim is to complete the census of MW GCs. The immediate goals are to estimate the astrophysical parameters, measuring their reddenings, extinctions, distances, total luminosities, proper motions, sizes, metallicities and ages. We use the near-IR VVVX survey database, in combination with Gaia DR2 optical photometry, and with the Two Micron All Sky Survey (2MASS) photometry. We report the detection of a heretofore unknown Galactic Globular Cluster at $RA =$ 14:09:00.0; $DEC=-$65:37:12 (J2000). We calculate a reddening of $E(J-K_s)=(0.3\pm 0.03)$ mag and an extinction of $A_{K_s}=(0.15\pm 0.01)$ mag for this new GC. Its distance modulus and corresponding distance were measured as $(m-M)=(15.93\pm0.03)$ mag and $D=(15.5\pm1.0)$ kpc, respectively. We estimate the metallicity and age by comparison with known GCs and by fitting PARSEC and Dartmouth isochrones, finding $[Fe/H]=(-0.70\pm0.2)$ dex and $t=(11.0\pm1.0)$ Gyr. The mean GC PMs from Gaia are $μ_{α^\ast}=(-4.68 \pm 0.47 )$ mas $yr^{-1}$ and $μ_δ=(-1.34 \pm 0.45)$ mas $yr^{-1}$. The total luminosity of our cluster is estimated to be $M_{Ks}=(-7.76\pm 0.5)$ mag. We have found a new low-luminosity, old and metal-rich globular cluster, situated in the far side of the Galactic disk, at $R_{G}=11.2$ kpc from the Galactic centre, and at $z=1.0$ kpc below the plane. Interestingly, the location, metallicity and age of this globular cluster are coincident with the Monoceros Ring (MRi) structure.
