Antlia 2’s Role in Driving the Ripples in the Outer Gas Disk of the Galaxy
Antlia 2’s Role in Driving the Ripples in the Outer Gas Disk of the Galaxy
复制标题
Antlia 2 在推动银河系外气盘涟漪中的作用
DOI：
10.3847/1538-4357/ab4659
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
L. Hernquist
中科院分区：
文献类型：
--
作者：
S. Chakrabarti;P. Chang;A. Price;J. Read;L. Blitz;L. Hernquist
我们利用先前发表的、根据盖亚数据得出的新发现的 Antlia 2 矮星系的自行运动来计算其在宇宙学上最近的过去的轨道分布。利用这些观测驱动的轨道，我们使用测试粒子和平滑粒子流体动力学模拟来计算 Antlia 2 矮星系对银河系外 H i 盘的影响。我们发现具有低近心点~10 kpc 的轨道产生的扰动与观察到的外H i 盘扰动相匹配。我们根据盖亚数据独立地重新计算了 Antlia 2 矮星的自行，发现其自行为 (μαcosδ, μδ) = (−0.068, 0.032) ± (0.023, -0.031) mas yr−1，这与 Torrealba 等人的结果一致。在误差范围内，但给出较低的平均近心点，例如，对于我们的银河系基准模型，∼15 kpc。我们还表明，人马座矮星系的相互作用与观察到的外气盘的扰动并不相符。因此，Antlia 2 可能是在银河系外气盘中观察到的大扰动的驱动因素。 Antlia 2 矮星系当前的位置与早期对矮星系动力学分析的预测非常吻合，矮星系在外星系中引起了涟漪，特别是它的轨道几乎与银盘共面。如果 Antlia 2 矮星系造成了外星系盘的扰动，那么它将会有我们在这里预测的特定范围的自行；这可以很快用 Gaia DR-3 和 Gaia DR-4 数据进行测试。
We employ the earlier published proper motions of the newly discovered Antlia 2 dwarf galaxy derived from Gaia data to calculate its orbital distribution in the cosmologically recent past. Using these observationally motivated orbits, we calculate the effect of the Antlia 2 dwarf galaxy on the outer H i disk of the Milky Way, using both test particle and smoothed particle hydrodynamics simulations. We find that orbits with low pericenters, ∼10 kpc, produce disturbances that match the observed outer H i disk perturbations. We have independently recalculated the proper motion of the Antlia 2 dwarf from Gaia data and found a proper motion of (μαcosδ, μδ) = (−0.068, 0.032) ± (0.023, −0.031) mas yr−1, which agrees with results from Torrealba et al. within the errors, but gives lower mean pericenters, e.g., ∼15 kpc for our fiducial model of the Milky Way. We also show that the Sagittarius dwarf galaxy interaction does not match the observed perturbations in the outer gas disk. Thus, Antlia 2 may be the driver of the observed large perturbations in the outer gas disk of the Galaxy. The current location of the Antlia 2 dwarf galaxy closely matches that predicted by an earlier dynamical analysis of the dwarf galaxy that drove ripples in the outer Galaxy, and, in particular, its orbit is nearly coplanar to the Galactic disk. If the Antlia 2 dwarf galaxy is responsible for the perturbations in the outer Galactic disk, it would have a specific range of proper motions that we predict here; this can be tested soon with Gaia DR-3 and Gaia DR-4 data.
影响因子：
4.8
作者：
G. Torrealba;V. Belokurov;Sergey E. Koposov;T. Li;M. Walker;J. Sanders;A. Geringer-Sameth;D. Zucker
通讯作者：
G. Torrealba;V. Belokurov;Sergey E. Koposov;T. Li;M. Walker;J. Sanders;A. Geringer-Sameth;D. Zucker
DOI：
10.1088/0004-6256/140/5/1194
发表时间：
2010-07
期刊：
The Astronomical Journal
影响因子：
--
作者：
F. Bigiel;A. Leroy;F. Walter;L. Blitz;E. Brinks;W. D. Blok;B. M. U. Berkeley;Mpia Heidelberg;Nrao;U. Hertfordshire;U. C. Town;C. Observatories
通讯作者：
F. Bigiel;A. Leroy;F. Walter;L. Blitz;E. Brinks;W. D. Blok;B. M. U. Berkeley;Mpia Heidelberg;Nrao;U. Hertfordshire;U. C. Town;C. Observatories
影响因子：
4.8
作者：
J. Read;Matthew C. Walker;P. Steger
通讯作者：
J. Read;Matthew C. Walker;P. Steger