论文标题
映射h $ _ {2} $ d $^{+} $和n $ _ {2} $ h $^{+} $发射到Prestellar cores。使用燃气示踪剂测试倒塌的动态模型
Mapping the H$_{2}$D$^{+}$ and N$_{2}$H$^{+}$ emission towards prestellar cores. Testing dynamical models of the collapse using gas tracers
论文作者
论文摘要
Prestellar核心的研究至关重要，因为它们在恒星形成中设置了初始条件并确定恒星对象的最终质量。迄今为止，几个假设描述了它们的重力崩溃。我们使用2'x2'Maps（JCMT）进行详细的行分析和H $ _ {2} $ d $^{+} $ 110 -111和N $ _ {2} $ h $^{+h $^{+4-3 $ 4-3排放。我们的目标是通过比较建模的气体运动学和空间分布来测试最突出的动力学模型（H $ _ {2} $ d $^{+} $和N $ _ {2} $ _ {2} $ h $^{+} $ （L1521F）。我们使用Ratran执行详细的非LTE辐射转移建模，在其中比较了H $ _ {2} $ d $^{+} $和N $ _ {2} $ H $^{+} $的预测空间分布和线轮廓与所有核心的观测。为此，我们采用了从文献中获得的三个不同动力学模型预测的每个核心的物理结构：准平衡Bonnor-ebert Sphere（QE-BES），单数等温球（SIS）和Larson-Penston（LP）流动。我们的分析提供了Prestellar内核物理结构的更新图片。我们发现，在解释核心的气体发射时，可以清楚地排除SIS模型，但是需要更大的样品才能清楚地区分LP流，QE-BES和静态模型。所有崩溃模型都低估了气体排放的强度，最多几个因素朝着样本中唯一的原始核心核心，表明不同的动态发生在不同的进化核心阶段。如果将LP模型确认为较大的Prestellar核心样品，则表明它们可能通过从较大尺度的压缩或积聚气体来形成。如果确认了QE-BES模型，则意味着准静液压核可以存在于湍流ISM中。
The study of prestellar cores is critical as they set the initial conditions in star formation and determine the final mass of the stellar object. To date, several hypotheses are describing their gravitational collapse. We perform detailed line analysis and modelling of H$_{2}$D$^{+}$ 110 -111 and N$_{2}$H$^{+}$ 4-3 emission at 372 GHz, using 2'x2' maps (JCMT). Our goal is to test the most prominent dynamical models by comparing the modelled gas kinematics and spatial distribution (H$_{2}$D$^{+}$ and N$_{2}$H$^{+}$) with observations towards four prestellar (L1544, L183, L694-2, L1517B) and one protostellar core (L1521f). We perform a detailed non-LTE radiative transfer modelling using RATRAN, where we compare the predicted spatial distribution and line profiles of H$_{2}$D$^{+}$ and N$_{2}$H$^{+}$ with observations towards all cores. To do so, we adopt the physical structure for each core predicted by three different dynamical models taken from literature: Quasi-Equilibrium Bonnor-Ebert Sphere (QE-BES), Singular Isothermal Sphere (SIS), and Larson-Penston (LP) flow. Our analysis provides an updated picture of the physical structure of prestellar cores. We find that the SIS model can be clearly excluded in explaining the gas emission towards the cores, but a larger sample is required to differentiate clearly between the LP flow, the QE-BES and the static models. All models of collapse underestimate the intensity of the gas emission by up to several factors towards the only protostellar core in our sample, indicating that different dynamics take place in different evolutionary core stages. If the LP model is confirmed towards a larger sample of prestellar cores, it would indicate that they may form by compression or accretion of gas from larger scales. If the QE-BES model is confirmed, it means that quasi hydrostatic cores can exist within turbulent ISM.
