论文标题
轨道卫星对恒星形成速率演变和金属性变化的影响类似银道的光盘
Impact of orbiting satellites on star formation rate evolution and metallicity variations in Milky Way-like discs
论文作者
论文摘要
目前，至少有一次主要合并正在MW中进行。 SGR矮人球形星系正在潮汐破坏，而MW绕着MW绕，其近距离通道在外部扰动MW盘。在这项工作中，使用一系列流体动力学模拟，我们研究了准偏置SGR样轨道上的较大矮星星系如何影响MW样圆盘内的恒星形成活性。首先，我们确认与轨道卫星的相互作用增强了宿主星系中的恒星形成速率。但是，在非常接近的通道（$ <20 $ kpc）的巨大（$> 2 \ times 10^{10} m_ \ odot $）的气体贫困卫星中检测到突出的短时秤。在富含气体的卫星的情况下，尽管我们看到恒星形成的大幅度增强，但我们并未检测到宿主恒星形成历史上的突出峰。这可以通过从卫星中剥离的气体的稳定积聚来解释，这使宿主的恒星形成速率的短期变化平滑。重要的是，卫星扰动的影响，尤其是其第一个相遇，主要是在主机的外部〜（$> 10 $ kpc）盘中。我们还发现，卫星的近距通过导致宿主中大量的低金属恒星形成，而在卫星气体中，卫星中最突出的效果是最突出的，从而导致平均恒星金属性稀释，后者是在大型卫星的第一个丁香卫星通道后不久稀释。我们的模拟支持SGR Galaxy的最新段落与太阳街区的星形爆发之间的因果关系。但是，为了在其第一个中心（$ \ 6 $ gyr）中复制SF爆发，我们需要非常接近的围式通道（$ <20 $ kpc），随后SGR前体的大量质量损失。
At least one major merger is currently taking place in the MW. The Sgr dwarf spheroidal galaxy is being tidally destroyed while orbiting around the MW, whose close passages perturb the MW disc externally. In this work, using a series of hydrodynamical simulations, we investigate how massive dwarf galaxies on quasi-polar Sgr-like orbits impact the star formation activity inside the MW-like discs. First, we confirm that interactions with orbiting satellites enhance the star formation rate in the host galaxy. However, prominent short-time scale bursts are detected during the very close passages ($<20$ kpc) of massive ($>2\times 10^{10} M_\odot$) gas-poor satellites. In the case of gas-rich satellites, while we see a substantial enhancement of the star formation on a longer time scale, we do not detect prominent peaks in the star formation history of the host. This can be explained by the steady accretion of gas being stripped from the satellite, which smoothens short-term variations in the star formation rate of the host. It is important that the impact of the satellite perturbations, especially its first encounters, is seen mainly in the outer~($>10$ kpc) disc of the host. We also found that the close passages of satellites cause the formation of a substantial amount of low-metallicity stars in the host, and the effect is the most prominent in the case of gas infall from the satellites resulting in the dilution of the mean stellar metallicity soon after the first pericentric passage of massive satellites. Our simulations are in favour of causality between the recent passages of the Sgr galaxy and the bursts of the star formation in the solar neighbourhood~($\approx 1$ and $\approx 2$ Gyr ago); however, in order to reproduce the SF burst at its first infall ($\approx 6$ Gyr), we require a very close pericentric passage ($<20$ kpc) with subsequent substantial mass loss of the Sgr precursor.
