Herschel 36光谱中的异常弥散星际带。I.几个DIB上旋转激发的CH和CH +吸收和强的、扩展的红翼的观测
Anomalous Diffuse Interstellar Bands in the Spectrum of Herschel 36. I. Observations of Rotationally Excited CH and CH+ Absorption and Strong, Extended Redward Wings on Several DIBs
摘要：
沿着赫歇尔36的视线，在5780.5、5797.1、6196.0和6613.6 A处发现了异常宽的弥漫星际带（DIB），这颗恒星照亮了H II区域Messier 8的明亮沙漏区域。星际吸收从激发CH+在J=1水平和激发CH在J=3/2水平也被看到。据我们所知，无论是那些激发的分子线，也没有这样强烈的扩展DIBs以前被看作是从星际气体的吸收。这些不寻常的特征似乎出现在赫歇尔36附近的一个小区域，该区域包含视线中大部分的中性星际物质。该区域的CH+和CH被邻近的红外源Her 36 SE的强远红外辐射辐射激发。类似地，DIB向Herschel 36的加宽可能是由于相对小的极性载体分子的紧密间隔的高J旋转能级的辐射泵浦。如果DIB载流子的激发转动态的这幅图是正确的，并且适用于大多数DIB，那么2.7度的宇宙微波背景可能设定了已知DIB的最小宽度（约0.35 A），分子过程和/或局部辐射场产生了对于较宽的DIB所发现的较大宽度。尽管在星系团NGC 6530内有强烈的局部紫外辐射场，但在赫歇尔36的光谱中没有发现以前未检测到的等效宽度大于10 mA的DIB，这表明这种强场对已知DIB的载流子的解离或电离都不会产生具有容易检测到的DIB样特征的新载流子。注意到其他几个DIB的可能相关的轮廓异常。
英文摘要：
Anomalously broad diffuse interstellar bands (DIBs) at 5780.5, 5797.1, 6196.0, and 6613.6 A are found in absorption along the line of sight to Herschel 36, the star illuminating the bright Hourglass region of the H II region Messier 8. Interstellar absorption from excited CH+ in the J=1 level and from excited CH in the J=3/2 level is also seen. To our knowledge, neither those excited molecular lines nor such strongly extended DIBs have previously been seen in absorption from interstellar gas. These unusual features appear to arise in a small region near Herschel 36 which contains most of the neutral interstellar material in the sight line. The CH+ and CH in that region are radiatively excited by strong far-IR radiation from the adjacent infrared source Her 36 SE. Similarly, the broadening of the DIBs toward Herschel 36 may be due to radiative pumping of closely spaced high-J rotational levels of relatively small, polar carrier molecules. If this picture of excited rotational states for the DIB carriers is correct and applicable to most DIBs, the 2.7 degree cosmic microwave background may set the minimum widths (about 0.35 A) of known DIBs, with molecular processes and/or local radiation fields producing the larger widths found for the broader DIBs. Despite the intense local UV radiation field within the cluster NGC 6530, no previously undetected DIBs stronger than 10 mA in equivalent width are found in the optical spectrum of Herschel 36, suggesting that neither dissociation nor ionization of the carriers of the known DIBs by this intense field creates new carriers with easily detectable DIB-like features. Possibly related profile anomalies for several other DIBs are noted.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
