The physical properties of the dust in the RCW 120 H ii region as seen by Herschel
The physical properties of the dust in the RCW 120 H ii region as seen by Herschel
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赫歇尔观察到的 RCW 120 H ii 区域灰尘的物理特性
DOI：
10.1051/0004-6361/201014657
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发表时间：
2010
影响因子：
6.5
通讯作者：
Anderson L
中科院分区：
文献类型：
--
作者：
Anderson L
RCW 120是一个经过充分研究的银河系H ii附近区域，其周围正在形成星星。先前的工作表明，它在中红外波长处显示出气泡形态，并且在亚毫米波长处观察到大量收集的中性材料层。由于光解离区边界和收集层的明确定义，它是研究触发星星形成的“收集-坍缩”过程的理想实验室。利用Herschel空间天文台100、160、250、350和500μm的观测资料，结合Spitzer和APEX-LABOCA的观测资料，首次实现了高角分辨率的H ii区全谱能量分布图的绘制。此外，我们希望了解灰尘的发射率指数，β，是有关的灰尘temperature.MethodsWe确定灰尘温度在选定的区域的RCW 120字段通过拟合其光谱能量分布（SED），使用孔径测光。此外，我们适合的SED提取的网格的位置，以创建一个temperature map.ResultsWe找到一个梯度的尘埃温度，范围从30 K的内部RCW 120，到~20 K的PDR中收集的材料，到~10 K朝向当地的红外暗云和冷灯丝。还有一个额外的，更热（~100 K）的尘埃排放，我们不调查在这里。我们的研究结果表明，RCW 120是在破坏PDR描绘其气泡形态的过程中。它内部泄漏的辐射可能会影响下一代恒星的形成。我们发现支持拟合温度和β之间的反相关性，与先前发现的大致一致。Herschel数据的波长覆盖范围的扩大大大增加了这一结果的可靠性。
ContextRCW 120 is a well-studied, nearby Galactic H ii region with ongoing star formation in its surroundings. Previous work has shown that it displays a bubble morphology at mid-infrared wavelengths, and has a massive layer of collected neutral material seen at sub-mm wavelengths. Given the well-defined photo-dissociation region (PDR) boundary and collected layer, it is an excellent laboratory to study the “collect and collapse” process of triggered star formation. UsingHerschelSpace Observatory data at 100, 160, 250, 350, and 500μm, in combination withSpitzerand APEX-LABOCA data, we can for the first time map the entire spectral energy distribution of an H ii region at high angular resolution.AimsWe seek a better understanding of RCW 120 and its local environment by analysing its dust temperature distribution. Additionally, we wish to understand how the dust emissivity index,β, is related to the dust temperature.MethodsWe determine dust temperatures in selected regions of the RCW 120 field by fitting their spectral energy distribution (SED), derived using aperture photometry. Additionally, we fit the SED extracted from a grid of positions to create a temperature map.ResultsWe find a gradient in dust temperature, ranging from 30 K in the interior of RCW 120, to ~20 K for the material collected in the PDR, to ~10 K toward local infrared dark clouds and cold filaments. There is an additional, hotter (~100 K) component to the dust emission that we do not investigate here. Our results suggest that RCW 120 is in the process of destroying the PDR delineating its bubble morphology. The leaked radiation from its interior may influence the creation of the next generation of stars. We find support for an anti-correlation between the fitted temperature andβ, in rough agreement with what has been found previously. The extended wavelength coverage of theHerscheldata greatly increases the reliability of this result.