An irradiated jet in M 17
An irradiated jet in M 17
复制标题
M 17 中的受辐射射流
DOI：
10.1051/0004-6361/201220086
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发表时间：
2013
影响因子：
6.5
通讯作者：
C. Oliveira
中科院分区：
文献类型：
--
作者：
F. Comerón;A. Pasquali;C. Oliveira
上下文。m17是银河系附近被研究得最好的巨型HII区域之一。它还应该为被附近热恒星照射的完全电离喷流提供一个合适的环境。然而，到目前为止，在m17中还没有观察到这样的喷流。目标。我们报告了m17星云的可见光成像调查，目的是确定可能的激波激发星云。方法。我们通过以[OIII]， H +[NII]， [SII]和H的最强烈可见线为中心的窄带滤光片对m17进行了成像。我们获得了图像中唯一确定的射流状结构的后续光谱。我们还利用钱德拉x射线天文台发布的m17 x射线观测数据，以及超大望远镜和斯皮策太空望远镜获得的红外数据，寻找喷气驱动源的证据。结果。我们已经发现了在m17可见的HII区域发现的第一个喷气机。喷流由一组结点组成，其中两个结点相对于HII区域具有显著的径向速度，还有一个遥远的弧形明亮星云，可能代表了喷流驱动源强烈质量损失的早期插曲。由射流组成的结构的后续光谱，包括弧，通过揭示由于冲击中增强的碰撞激发而产生的强烈的[NII]和[SII]禁线，支持了这一解释。x射线源的存在，很可能是一个年轻的恒星物体，在射流发射源应该存在的位置加强了解释。我们确定了x射线源的暂定近红外对应物，尽管它与x射线源的标称位置相差1:00 9，这几乎是其位置不确定性半径的三倍。喷流结和弧的光谱中非常弱的[OI]发射表明它们几乎完全电离，与喷流传播的环境一致。
Context. M 17 is one of the best studied giant HII regions in our galactic neighborhood. It should also provide a suitable environment for the class of fully ionized jets externally irradiated by the presence of nearby hot stars. However, no such jets have been observed thus far in M 17. Aims. We report on a visible imaging survey of the M 17 nebula with the goal of identifying likely shock-excited nebulosities. Methods. We imaged M 17 through narrow-band filters centered on the most intense visible lines of [OIII], H +[NII], [SII], and H . We obtained follow-up spectroscopy of the only jet-like structure identified in the images. We also used published X-ray observations of M 17 obtained with the Chandra X-ray Observatory, as well as infrared data obtained with the Very Large Telescope and with the Spitzer Space Telescope, to look for evidence of a jet-driving source. Results. We have detected what appears to be the first jet identified in M 17 visible HII region. The jet is composed of a set of knots, two of which have significant radial velocities with respect to the HII region, and a distant arc-like bright nebulosity that may represent an early episode of intense mass loss by the jet-driving source. The follow-up spectra of the structures composing the jet, including the arc, support this interpretation by revealing intense forbidden lines of [NII] and [SII] due to enhanced collisional excitation in shocks. The presence of a X-ray source, most likely a young stellar object, at a position where the jet launching source should be expected to lie reinforces the interpretation. We identify a tentative near-infrared counterpart of the X-ray source, although it is o set by 1: 00 9 from the nominal position of the X-ray source, which is almost three times the radius of its positional uncertainty. The very weak [OI] emission in the spectra of the jet knots and the arc suggests that they are nearly fully ionized, in agreement with the environment in which the jet is propagating.