论文标题
表征巨大恒星形成团块中的[C II]线排放
Characterizing [C II] Line Emission In Massive Star Forming Clumps
论文作者
论文摘要
由于157.74微米[C II]线是恒星形成区域的主要冷却剂，因此通常用于推断星系的全球恒星形成速率。通过表征附近银河系形成的分子块的[C II]和远红外发射，可以确定是否来自此类团块的大量集合产生了乳化[C II]的发射，并且[C II]是否确实是全球恒星形成的可靠指标。我们使用索非亚空降天文台上的FIFI-LS仪器来描述[C II]和远红外观测，朝着四个致密的高质量，银河系团块。尽管相似，但[C II]与远红外光度比，L（[C II]）/L（fir）在这四个团块中的变化至少为140倍。特别是，对于AGAL313.576+0.324，尽管FIR发光度为24,000 l_sun，但仍未检测到[C II]线排放。 AGAL313.576+0.324位于L（[C II]）/L（FIR）与S_ν（63 micron）/S_ν（158微米）之间的经验相关曲线低于100倍以上。 AGAL313.576+0.324可能处于早期进化的“原始”相，紫外线不足以使碳离子化，或者在深层嵌入的``高度涂压'H II区域阶段，其中粉尘的粉尘衰减限制了UV量限制了离子化碳的区域，从而使无离子小沃尔姆的小沃尔姆斯的小沃尔姆斯的粉尘限制了。另外，它显然缺乏\ cii \，可能是由于对\ cii \的深度吸收而产生的，反对158微米连续体，或者通过前景材料对更明亮的线条排放的自我吸收，这可能会消除或减少Fifi-LS仪器仪器的宽光谱分辨率元素（〜250 km/s））
Because the 157.74 micron [C II] line is the dominant coolant of star-forming regions, it is often used to infer the global star-formation rates of galaxies. By characterizing the [C II] and far-infrared emission from nearby Galactic star-forming molecular clumps, it is possible to determine whether extragalactic [C II] emission arises from a large ensemble of such clumps, and whether [C II] is indeed a robust indicator of global star formation. We describe [C II] and far-infrared observations using the FIFI-LS instrument on the SOFIA airborne observatory toward four dense, high-mass, Milky Way clumps. Despite similar far-infrared luminosities, the [C II] to far-infrared luminosity ratio, L([C II])/L(FIR) varies by a factor of at least 140 among these four clumps. In particular, for AGAL313.576+0.324, no [C II] line emission is detected despite a FIR luminosity of 24,000 L_sun. AGAL313.576+0.324 lies a factor of more than 100 below the empirical correlation curve between L([C II])/L(FIR) and S_ν(63 micron)/S_ν(158 micron) found for galaxies. AGAL313.576+0.324 may be in an early evolutionary "protostellar" phase with insufficient ultraviolet flux to ionize carbon, or in a deeply embedded ``hypercompact' H II region phase where dust attenuation of UV flux limits the region of ionized carbon to undetectably small volumes. Alternatively, its apparent lack of \cii\, emission may arise from deep absorption of the \cii\, line against the 158 micron continuum, or self-absorption of brighter line emission by foreground material, which might cancel or diminish any emission within the FIFI-LS instrument's broad spectral resolution element (~250 km/s)
