The Rotation-Metallicity Relation for the Galactic Disk as Measured in the Gaia DR1 TGAS and APOGEE Data
The Rotation-Metallicity Relation for the Galactic Disk as Measured in the Gaia DR1 TGAS and APOGEE Data
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DOI：
10.1051/0004-6361/201629787
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发表时间：
2016-09
期刊：
影响因子：
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通讯作者：
C. Prieto;D. Kawata;M. Cropper
中科院分区：
文献类型：
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作者：
C. Prieto;D. Kawata;M. Cropper
先前的研究发现，薄盘和厚盘种群的银河系自转速度-金属丰度（V-[Fe/H]）关系分别显示出负斜率和正斜率。第一个盖亚数据发布包括Tycho-Gaia天体测量解决方案（TGAS）信息，我们使用它来分析严格选择的样本的V-[Fe/H]关系，具有足够高的天体测量精度。我们的目标是达到的V-[Fe/H]关系的斜率的解释。我们测量的V-[Fe/H]关系薄和厚盘星分类的基础上，他们的[$\alpha$/Fe]和[Fe/H]丰度。我们发现，对于薄盘中的恒星，dV/d[Fe/H]= -18 +/- 2 km/s/dex，而对于厚盘中的恒星，dV/d[Fe/H]= +23 +/- 10 km/s/dex，因此我们确认了斜率的不同符号。厚盘星dV/d[Fe/H]的负值与以前的研究一致，但TGAS和APOGEE数据的组合提供了更高的精度，即使系统误差可能超过+/-5 km/s/dex。我们对局部厚盘星dV/d[Fe/H]的平均测量显示出比以前的研究更平坦的斜率，但我们确认了一个显着的扩展和斜率对恒星[α/Fe]比的依赖性。使用一个简单的N体模型，我们证明了所观察到的趋势厚和薄盘可以解释所观察到的径向金属丰度梯度和轨道偏心率和金属丰度之间的相关性在厚盘。
Previous studies have found that the Galactic rotation velocity-metallicity (V-[Fe/H]) relations for the thin and thick disk populations show negative and positive slopes, respectively. The first Gaia Data Release includes the Tycho-Gaia Astrometric Solution (TGAS) information, which we use to analyze the V-[Fe/H] relation for a strictly selected sample with high enough astrometric accuracy. We aim to arrive at an explanation for the slopes of the V-[Fe/H] relationship. We measure the V-[Fe/H] relation for thin and thick disk stars classified on the basis of their [$\alpha$/Fe] and [Fe/H] abundances. We find dV/d[Fe/H]= -18 +/- 2 km/s/dex for stars in the thin disk and dV/d[Fe/H]= +23 +/- 10 km/s/dex for thick disk stars, so we confirm the different signs for the slopes. The negative value of dV/d[Fe/H] for thick disk stars is consistent with previous studies, but the combination of TGAS and APOGEE data provide higher precision, even though systematic errors could exceed +/-5 km/s/dex . Our average measurement of dV/d[Fe/H] for local thick disk stars shows a somewhat flatter slope than the previous studies, but we confirm a significant spread and a dependence of the slope on the [alpha/Fe] ratio of the stars. Using a simple N-body model, we demonstrate that the observed trend for the thick and thin disk can be explained by the observed radial metallicity gradients and the correlation between orbital eccentricity and metallicity in the thick disk.