论文标题
闪烁：新的高速h $ _2 $ o masers in Iras 18286 $ - $ 0959
FLASHING: New high-velocity H$_2$O masers in IRAS 18286$-$0959
论文作者
论文摘要
We discovered new high-velocity components of H$_2$O maser emission in one of the "water fountain" sources, IRAS~18286$-$0959, which has been monitored using the Nobeyama 45 m telescope in the new FLASHING (Finest Legacy Acquisitions of SiO- and H$_2$O-maser Ignitions by Nobeyama Generation) project since 2018 December. Maser Spectra显示出新的，极高的扩展速度（$> $> $> $> $ 200〜 km〜s $^{ - 1} $在视线中投影）组件，其中一些相对于系统性速度对称地位于光谱中。他们还在2019年3月与Kava（KVN和Vera合并阵列）一起绘制了它们。与其他高速速度组件（50--200〜km〜s $^{ - 1} $）相比，我们找到了一些靠近中央恒星系统的Maser组件，这些组件已被确认与已知的双极流出相关。新组件将在2011年未检测到的2011年之后的300〜km〜s $^{ - 1} $（-1} $（很快）以上的速度超过300〜km〜S $^{ - 1} $中。最快的新组件似乎表明在这些光谱中快速减速，但是我们目前的监控仍然太稀疏，无法明确确认（高达50〜 km〜s $^s $^{ - 1} $ yr $^{ - 1} $），太短了，无法透露它们的终端扩张性，而揭示了它们的扩张velocity（$ exp} \ sim $ 120〜km〜s $^{ - 1} $）。这种极端速度组件的未来发生可能会提供一个很好的机会来调查可能的反复出发点火开关。因此，父母包膜的雕塑将被快速射流所夹带的密集气体所追踪，并表现出相对稳定的Maser特征的壮观分布。
We discovered new high-velocity components of H$_2$O maser emission in one of the "water fountain" sources, IRAS~18286$-$0959, which has been monitored using the Nobeyama 45 m telescope in the new FLASHING (Finest Legacy Acquisitions of SiO- and H$_2$O-maser Ignitions by Nobeyama Generation) project since 2018 December. The maser spectra show new, extremely high expansion velocities ($>$200~km~s$^{-1}$ projected in the line of sight) components, some of which are located symmetrically in the spectrum with respect to the systemic velocity. They were also mapped with KaVA (KVN and VERA Combined Array) in 2019 March. We located some of these maser components closer to the central stellar system than other high velocity components (50--200~km~s$^{-1}$) that have been confirmed to be associated with the known bipolar outflow. The new components would flash in the fast collimated jet at a speed over 300~km~s$^{-1}$ (soon) after 2011 when they had not been detected. The fastest of the new components seem to indicate rapid deceleration in these spectra, however our present monitoring is still too sparse to unambiguously confirm it (up to 50~km~s$^{-1}$yr$^{-1}$) and too short to reveal their terminal expansion velocity, which will be equal to the expansion velocity that has been observed ($v_{\rm exp}\sim$120~km~s$^{-1}$). Future occurrences of such extreme velocity components may provide a good opportunity to investigate possible recurrent outflow ignitions. Thus sculpture of the parental envelope will be traced by the dense gas that is entrained by the fast jet and exhibits spectacular distributions of the relatively stable maser features.
