标题： 在VVVX巡天中发现的银河系一个新的低光度球状星团 显示英文标题

标题： A new low-luminosity globular cluster discovered in the Milky Way with the VVVX survey

摘要： VISTA在银河系延伸调查中的变量（VVVX）使以前未探索的银河系内部区域得以研究。 我们正在寻找新的球状星团（GC）候选者，旨在完成银河系GC系统的普查。 我们使用近红外VVVX调查和2MASS数据集，以及光学Gaia EDR3测光和其精确的自行（PMs）来搜索和表征新的GC。 我们报告发现了一个新的银河系GC，命名为Garro 02，位于赤经=18:05:51.1，赤纬=-17:42:02，l=12.042度，b=+1.656度。 进行自行去污染过程后，我们建立了一个包含所有星团成员的最终目录，并对其进行了测光分析。 我们在近红外计算出消光为$E(J-K_s)=1.07\pm 0.06$mag，消光为$A_{Ks}=0.79\pm 0.04$mag；而在光学波段为$E(BP-RP)=2.40\pm 0.01$mag和$A_{G}=4.80\pm 0.02$mag。 其日心距离为$D=5.6\pm 0.8$kpc，这将Garro 02置于银河中心距离为$R_G=2.9$kpc处，并位于银河平面以上Z=0.006 kpc的位置。 我们通过与已知的GCs比较和拟合PARSEC等值线，估算了金属丰度和年龄，得到[Fe/H]$=-1.30\pm 0.2$ dex，年龄=$12\pm 2$ Gyr。 我们得到了该星团的平均自行PM为$(\mu_{\alpha}^{\ast}, \mu_{\delta}) = (-6.07\pm 0.62, -6.15\pm 0.75)$ mas yr$^{-1}$。 我们在近红外波段计算了该星团的光度为$M_{Ks}=-7.52\pm 1.23$ mag，这相当于$M_{V}=-5.44$ mag。 核心和潮汐半径来自径向密度分布分别是$r_c =1.25\pm 0.27$弧分（2.07 pc）和$r_t = 7.13\pm 3.83$弧分（11.82 pc）。 我们确认 Garro 02 为一个新的真实的银河系球状星团，位于银河系核球中。 它是一个低光度、贫金属和古老的球状星团，是银河系整个生命期间发生强烈动力学过程中的幸运幸存者。 显示英文摘要

摘要： The VISTA Variables in the Via L\'actea Extended Survey (VVVX) allows probing previously unexplored regions of the inner Milky Way (MW). We are looking for new candidate globular clusters (GCs), with the aim of completing the census of the MW GC system. We searched and characterised new GCs, using a combination of the near-IR VVVX survey and 2MASS datasets, and the optical Gaia EDR3 photometry and its precise proper motions (PMs). We report the discovery of a new Galactic GC, named Garro 02, situated at RA=18:05:51.1, Dec=-17:42:02 and l=12.042 deg, b=+1.656 deg. Performing a PM-decontamination procedure, we built a final catalogue with all cluster members, on which we performed a photometric analysis. We calculated a reddening of $E(J-K_s)=1.07\pm 0.06$ mag and extinction of $A_{Ks}=0.79\pm 0.04$ mag in the near-IR; while $E(BP-RP)=2.40\pm 0.01$ mag and $A_{G}=4.80\pm 0.02$ mag in optical passbands. Its heliocentric distance is $D=5.6\pm 0.8$ kpc, which places Garro 02 at a Galactocentric distance of $R_G=2.9$ kpc and Z=0.006 kpc above the Galactic plane. We estimated the metallicity and age by comparison with known GCs and by fitting PARSEC isochrones, finding [Fe/H]$=-1.30\pm 0.2$ dex and age=$12\pm 2$ Gyr. We derived the mean cluster PM of $(\mu_{\alpha}^{\ast}, \mu_{\delta}) = (-6.07\pm 0.62, -6.15\pm 0.75)$ mas yr$^{-1}$. We calculated the cluster luminosity in the near-IR of $M_{Ks}=-7.52\pm 1.23$ mag, which is equivalent to $M_{V}=-5.44$ mag. The core and tidal radii from the radial density profile are $r_c =1.25\pm 0.27$ arcmin (2.07 pc) and $r_t = 7.13\pm 3.83$ arcmin (11.82 pc), respectively. We confirm Garro 02 as a new genuine Galactic GC, located in the MW bulge. It is a low-luminosity, metal-poor, and old GC, and it is a lucky survivor of the strong dynamical processes that occurred during the MW's entire life.