Goicoechea Javier R, Teyssier D, Etxaluze M, Goldsmith P F, Ossenkopf V, Gerin M, Bergin E A, Black J H, Cernicharo J, Cuadrado S, Encrenaz P, Falgarone E, Fuente A, Hacar A, Lis D C, Marcelino N, Melnick G J, Müller H S P, Persson C, Pety J, Röllig M, Schilke P, Simon R, Snell R L, Stutzki J
Instituto de Ciencia de Materiales de Madrid (CSIC). Calle Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain.
Herschel Science Centre, ESA/ESAC, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid, Spain.
Astrophys J. 2015 Oct 10;812(1). doi: 10.1088/0004-637X/812/1/75.
We present the first 7.5'×11.5' velocity-resolved (0.2 km s) map of the [C ii] 158 m line toward the Orion molecular cloud 1 (OMC 1) taken with the /HIFI instrument. In combination with far-infrared (FIR) photometric images and velocity-resolved maps of the H41 hydrogen recombination and CO =2-1 lines, this data set provides an unprecedented view of the intricate small-scale kinematics of the ionized/PDR/molecular gas interfaces and of the radiative feedback from massive stars. The main contribution to the [C ii] luminosity (85 %) is from the extended, FUV-illuminated face of the cloud (>500, >5×10 cm) and from dense PDRs (≳10, ≳10 cm) at the interface between OMC 1 and the H ii region surrounding the Trapezium cluster. Around ~15 % of the [C ii] emission arises from a different gas component without CO counterpart. The [C ii] excitation, PDR gas turbulence, line opacity (from [C ii]) and role of the geometry of the illuminating stars with respect to the cloud are investigated. We construct maps of the [C ii]/ and / ratios and show that [C ii]/ decreases from the extended cloud component (10-10) to the more opaque star-forming cores (~10-10). The lowest values are reminiscent of the "[C ii] deficit" seen in local ultra-luminous IR galaxies hosting vigorous star formation. Spatial correlation analysis shows that the decreasing [C ii]/ ratio correlates better with the column density of dust through the molecular cloud than with /. We conclude that the [C ii] emitting column relative to the total dust column along each line of sight is responsible for the observed [C ii]/ variations through the cloud.
我们展示了首张使用/HIFI仪器拍摄的朝向猎户座分子云1（OMC 1）的[C ii] 158微米谱线的速度分辨（约0.2千米每秒）地图，尺寸约为7.5英尺×11.5英尺。结合远红外（FIR）光度图像以及H41氢复合线和CO =2-1线的速度分辨地图，该数据集提供了关于电离/光致电离气体区域/分子气体界面复杂的小尺度运动学以及大质量恒星辐射反馈的前所未有的视角。对[C ii]光度的主要贡献（约85%）来自云团延伸的、受远紫外光照射的表面（>500，>5×10厘米）以及OMC 1与围绕梯形星团的H ii区域之间界面处的致密光致电离气体区域（≳10，≳10厘米）。约15%的[C ii]发射来自没有CO对应物的不同气体成分。研究了[C ii]激发、光致电离气体区域的湍流、谱线不透明度（来自[C ii]）以及照亮恒星的几何形状相对于云团的作用。我们构建了[C ii]/和/比值的地图，并表明[C ii]/从延伸的云团成分（约1×10⁻¹⁰）到更不透明的恒星形成核心（约1×10⁻¹¹）逐渐降低。最低值让人联想到在有活跃恒星形成的本地超亮红外星系中看到的“[C ii]亏损”。空间相关性分析表明，[C ii]/比值的降低与穿过分子云的尘埃柱密度的相关性比与/的相关性更好。我们得出结论，沿着每条视线方向，相对于总尘埃柱的[C ii]发射柱是造成整个云团中观测到的[C ii]/变化的原因。
