Globular clusters with Gaia
Globular clusters with Gaia
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球状星团与盖亚
DOI：
10.1093/mnras/stx079
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发表时间：
2017
影响因子：
4.8
通讯作者：
S. Marinoni
中科院分区：
文献类型：
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作者：
E. Pancino;E. Pancino;M. Bellazzini;G. Giuffrida;G. Giuffrida;S. Marinoni;S. Marinoni
对盖亚数据中拥挤字段的处理在几年后才会成为现实。特别是对于球状星团，只有任务结束时的数据（2022-2023年公开）才会进行必要的充分拥挤处理，并达到足够的质量来处理最微弱的恒星。因此，除混和除污管道的工作仍在进行中。我们描述了不同盖亚仪器的管道现状，并根据现有信息建立了任务结束拥挤误差的模型。然后，我们将发射后的名义Gaia性能（由于估计的拥挤误差而适当恶化）应用于一组18个具有不同浓度、距离和场污染的模拟球状星团。我们得出的结论是，在大多数星团中，将有103-104颗恒星的天文测量性能几乎没有受到拥挤（污染小于1 mmag）的影响。最大的限制因素将是星团拥挤，而不是星团拥挤：污染最严重的星团将只包含10-100颗干净的恒星。我们还得出结论：(1)系统固有运动和视差将被确定为1%或更好，最高可达15 kpc，附近星团的视向速度将达到几km/s；（ii）内部运动学将具有前所未有的质量，集群质量将确定为10%，直至15 KPC及以上，并且有可能在10 KPC及以上的集群子种群的运动学中识别出几公里/秒或更小的差异（如果有的话）；（iii）最亮的恒星（V<17等）将具有空间质量的宽视场光度测量（毫等误差），所有盖亚光度测量在绝对光度校准上都将有1-3%的误差。
The treatment of crowded fields in Gaia data will only be a reality in a few years from now. In particular, for globular clusters, only the end-of-mission data (public in 2022-2023) will have the necessary full crowding treatment and will reach sufficient quality for the faintest stars. As a consequence, the work on the deblending and decontamination pipelines is still ongoing. We describe the present status of the pipelines for different Gaia instruments, and we model the end-of-mission crowding errors on the basis of available information. We then apply the nominal post-launch Gaia performances, appropriately worsened by the estimated crowding errors, to a set of 18 simulated globular clusters with different concentration, distance, and field contamination. We conclude that there will be 103-104 stars with astrometric performances virtually untouched by crowding (contaminated by <1 mmag) in the majority of clusters. The most limiting factor will be field crowding, not cluster crowding: the most contaminated clusters will only contain 10-100 clean stars. We also conclude that: (i) the systemic proper motions and parallaxes will be determined to 1% or better up to 15 kpc, and the nearby clusters will have radial velocities to a few km/s ; (ii) internal kinematics will be of unprecendented quality, cluster masses will be determined to 10% up to 15 kpc and beyond, and it will be possible to identify differences of a few km/s or less in the kinematics (if any) of cluster sub-populations up to 10 kpc and beyond; (iii) the brightest stars (V<17 mag) will have space-quality, wide-field photometry (mmag errors), and all Gaia photometry will have 1-3% errors on the absolute photometric calibration.