HERSCHEL OBSERVATIONS OF EXTRA-ORDINARY SOURCES: H2S AS A PROBE OF DENSE GAS AND POSSIBLY HIDDEN LUMINOSITY TOWARD THE ORION KL HOT CORE
HERSCHEL OBSERVATIONS OF EXTRA-ORDINARY SOURCES: H2S AS A PROBE OF DENSE GAS AND POSSIBLY HIDDEN LUMINOSITY TOWARD THE ORION KL HOT CORE
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DOI：
10.1088/0004-637x/781/2/114
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发表时间：
2014-02-01
影响因子：
4.9
通讯作者：
Kleshcheva, M.
中科院分区：
文献类型：
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作者：
Crockett, N. R.;Bergin, E. A.;Kleshcheva, M.
我们提出了Herschel/HIFI观测的轻氢化物H2S从猎户座Kleinmann-Low星云（猎户座KL）的全光谱扫描作为Herschel观测的超普通源GT（保证时间）关键程序的一部分。总共，我们分别从（H2S）-S-32、（H2S）-S-34和（H2S）-S-33观察到52、24和8个未混合或轻微混合的特征。我们只分析所谓的热核心的发射，但从高原，扩展的脊，和/或紧凑的脊发射也被检测到。考虑到不确定性，邻位和帕拉H2S的旋转图遵循直线，得出T-rot = 141 +/- 12 K。这表明H2S处于局部热力学平衡状态，其特征在于单一的动力学温度或强烈的远红外辐射场正在重新分布种群，以产生观察到的趋势。我们认为后一种情况更有可能，并发现最高激发态（E-up大于或接近1000 K）可能主要由辐射泵浦填充。我们推导出柱密度，N-tot（（H2S）-S-32）= 9.5 +/- 1.9 × 10（17）cm（-2），气体动力学温度，T-kin = 120 +/-（13）（10）K，并且对于H2S排放气体，限制H-2体积密度，n（H2）大于或接近9 × 10（7）cm（-3）。这些结果指出，H2S起源于明显密集的，严重嵌入的气体中，可能非常接近一个隐藏的自发光源（或源），这是可以想象的猎户座KL的高亮度。我们还推导出H2S邻位/帕拉比为1.7 +/-0.8，并将HDS/H2S的上限设定为< 4.9 × 10（-3）。
We present Herschel/HIFI observations of the light hydride H2S obtained from the full spectral scan of the Orion Kleinmann-Low nebula (Orion KL) taken as part of the Herschel Observations of EXtra-Ordinary Sources GT (guaranteed time) key program. In total, we observe 52, 24, and 8 unblended or slightly blended features from (H2S)-S-32, (H2S)-S-34, and (H2S)-S-33, respectively. We only analyze emission from the so-called hot core, but emission from the plateau, extended ridge, and/or compact ridge are also detected. Rotation diagrams for ortho and para H2S follow straight lines given the uncertainties and yield T-rot = 141 +/- 12 K. This indicates H2S is in local thermodynamic equilibrium and is well characterized by a single kinetic temperature or an intense far-IR radiation field is redistributing the population to produce the observed trend. We argue the latter scenario is more probable and find that the most highly excited states (E-up greater than or similar to 1000 K) are likely populated primarily by radiation pumping. We derive a column density, N-tot((H2S)-S-32) = 9.5 +/- 1.9 x 10(17) cm(-2), gas kinetic temperature, T-kin = 120 +/-(13)(10) K, and constrain the H-2 volume density, n(H2) greater than or similar to 9 x 10(7) cm(-3), for the H2S emitting gas. These results point to an H2S origin in markedly dense, heavily embedded gas, possibly in close proximity to a hidden self-luminous source (or sources), which are conceivably responsible for Orion KL's high luminosity. We also derive an H2S ortho/para ratio of 1.7 +/- 0.8 and set an upper limit for HDS/H2S of < 4.9 x 10(-3)