论文标题
用Gaia EDR3 +以银河系盘来测量流动运动
Measuring the Streaming motion in the Milky Way disc with Gaia EDR3 +
论文作者
论文摘要
我们将银河盘的3D运动学映射到来自太阳的3.5 kpc,距离星系中平面的0.75 kpc。为此,我们将\ gedrthree {}的高质量天文统计与\ gdrtwo {}的HeliePentric偏见速度和光谱调查(包括\ apogee {},\ galah {},and \ lamost {})相结合。我们为平均速度场构建一个轴对称模型,并以星级的基础减去轴对称模型,以获取半乳突中心成分(\ vphi {},\ vr,\ vz)中的残余速度场和\ vlos {}。使用功率谱对速度残差进行量化,我们发现Midplane($ | | | <0.25 $ kpc)is($ | <0.25 $ kpc)is($ a_DActor)的峰值功率($ a/$ [\ rm \ kmms {}])是($ a_DActor) los} $)=($ 4.2,8.5,2.6,4.6 $),$ 0.25 <| z |/[{{\ rm kpc}] <0.5 $,($ a_DAction,a _ _ {\ rm rm rm},a _ {\ rm z} $ 0.5 <| z |/[{\ rm kpc}] <0.75 $,is($ a_Dist,a _ {\ rm rm r},a _ {\ rm z},a _ {\ rm los} $)我们的结果提供了对光盘和各个组件中流动运动的复杂测量。我们发现,流在\ vr中是最重要的,并且在所有高度($ | z | $)中都进行了探测,但在其他组件中也不可忽略。此外,我们发现速度场中的模式与银河系中的螺旋臂模型在空间上重叠。我们的模拟表明,破坏螺旋臂的相结合可以在速度场中产生此类残差,其中径向分量是主导的,就像在实际数据中一样。我们还发现,随着时间的推移,残余运动的幅度和物理尺度都会减少。
We map the 3D kinematics of the Galactic disc out to 3.5 kpc from the Sun, and within 0.75 kpc from the midplane of the Galaxy. To this end, we combine high quality astrometry from \gedrthree{}, with heliocentric line-of-sight velocities from \gdrtwo{}, and spectroscopic surveys including \apogee{}, \galah{}, and \lamost{}. We construct an axisymmetric model for the mean velocity field, and subtract this on a star-by-star basis to obtain the residual velocity field in the Galactocentric components (\vphi{}, \vR, \vz), and \vlos{}. The velocity residuals are quantified using the power spectrum, and we find that the peak power ($A/$[\rm \kms{}]) in the midplane ($|z|<0.25$ kpc) is ($A_ϕ,A_{\rm R},A_{\rm Z},A_{\rm los}$)=($4.2,8.5,2.6,4.6$), at $0.25 < |z|/[{\rm kpc}] < 0.5$, is ($A_ϕ,A_{\rm R},A_{\rm Z},A_{\rm los}$)=($4.0,7.9,3.6,5.3$), and at $0.5 < |z|/[{\rm kpc}] < 0.75$, is ($A_ϕ,A_{\rm R},A_{\rm Z},A_{\rm los}$)=($1.9,6.9,5.2,6.4$). Our results provide a sophisticated measurement of the streaming motion in the disc and in the individual components. We find that streaming is most significant in \vR, and at all heights ($|Z|$) probed, but is also non-negligible in other components. Additionally, we find that patterns in velocity field overlap spatially with models for Spiral arms in the Galaxy. Our simulations show that phase-mixing of disrupting spiral arms can generate such residuals in the velocity field, where the radial component is dominant, just as in real data. We also find that with time evolution both the amplitude and physical scale of the residual motion decrease.