Differences in star formation activity between tidally triggered and isolated bars: a case study of NGC?4303 and NGC?3627
Differences in star formation activity between tidally triggered and isolated bars: a case study of NGC?4303 and NGC?3627
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潮汐触发条和孤立条之间恒星形成活动的差异：NGC?4303 和 NGC?3627 的案例研究
DOI：
10.1093/mnras/stab3330
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发表时间：
2021
影响因子：
4.8
通讯作者：
Okamoto Takashi
中科院分区：
文献类型：
--
作者：
Iles Elizabeth J;Pettitt Alex R;Okamoto Takashi
星系棒是星系演化的重要驱动力，但它们如何影响星际介质和相应的恒星形成，目前尚不清楚。我们给出了两个具有不同形成机制的棒星系的模拟结果，这些棒星系是孤立形成的，还是通过潮汐相互作用形成的，以考虑恒星形成的空间和时间变化趋势。我们将重点放在砂坝形成的早期（<1 Gyr）时期，以便清楚地识别相互作用。邻近的NGC 4303（孤立的）和NGC 3627（相互作用历史）被选择作为观测类似物来调整这些模拟。无论形成机制如何，两种模型都显示出相似的内部动力学特征，尽管相互作用似乎促进了外盘速度结构中的杆臂断裂。这两个条形图触发了类似的恒星形成加速（79%;66%），而这种相互作用也触发了早先的31%的爆发。在表面气体和恒星形成速率的关系中观察到明显的形态学依赖性。在这两种情况下，条形部分明显是最陡的；手臂与整个椎间盘的平均值相似；而臂间显然是最浅的。潮汐盘的一个显著特征是存在中等密度的、低效的恒星形成气体，这些气体主要局限于光盘外的潮汐碎片。潮汐盘也表现出一种独特的趋势，即恒星形成效率呈放射状增加，而恒星形成的明显缺乏，这种趋势在中心和杆端之间的棒子上持续存在。这些都是相互作用后识别被禁系统的潜在特征。
Galactic bars are important drivers of galactic evolution, and yet how they impact the interstellar medium and correspondingly star formation, remains unclear. We present simulation results for two barred galaxies with different formation mechanisms, bars formed in isolation or via a tidal interaction, to consider the spatially and temporally varying trends of star formation. We focus on the early (<1 Gyr) epoch of bar formation so that the interaction is clearly identifiable. The nearby NGC 4303 (isolated) and NGC 3627 (interaction history) are selected as observational analogues to tailor these simulations. Regardless of formation mechanism, both models show similar internal dynamical features, although the interaction appears to promote bar-arm disconnection in the outer disc velocity structure. Both bars trigger similar boosts in star formation (79 per cent; 66 per cent), while the interaction also triggers an earlier 31 per cent burst. Significant morphological dependence is observed in the relation between surface gas and star formation rate. In both cases, the bar component is notably steepest; the arm is similar to the overall disc average; and the interarm clearly the shallowest. A distinguishable feature of the tidal disc is the presence of moderately dense, inefficiently star-forming gas mostly confined to tidal debris outside the optical disc. The tidal disc also exhibits a unique trend of radially increasing star formation efficiency and a clear dearth of star formation which persists along the bar between the centre and bar ends. These are potential signatures for identifying a barred system post-interaction.