Infrared detection of Galactic planetary nebulae

该项目将研究在红外波长探测行星状星云并确定其特征的技术。银河系中有大约3，500个已知的PN，其中大多数是近年来在银河平面（GP）调查中发现的光学波长，特别是在H-α中（例如MASH -帕克等人2006; IPHAS- Sabin等人2014）。从模型的人口估计变化从~6000到~45000取决于是否双星是一个要求或是否单星也可以形成PN。目前，这是恒星演化中的一个悬而未决的问题。现在有一个移动到红外探测技术，这是不太容易银河系灭绝和探测更长的视线。该项目将建立在UWISH 2调查的基础上，UWISH 2调查是对北方GP在2.12微米处的分子氢（H2）的v=1- 0 S（1）振转谱线的首次成像调查（Froebrich等人，2015），这导致检测到约300个PN候选（B= +/- 1.5度），其中约2/3是在H-α中未观察到的新检测，约50%具有双极形态。该项目的第一阶段将是减少和发布这些物体的一个子集的长缝K波段光谱，以进一步确定它们的PN性质（2016年7月在WHT获得的观测结果），并适当跟进Br-伽马和H2线成像（提交的提案）以及未来可能的IFS观测。在该项目的第二阶段，将通过PDR模型探索重组和分子线发射光谱/图像的建模，并受到观测的约束（学生将参加2017年多云研讨会）。其目的是产生一套发射线和连续模式的PN在红外作为一个功能的演变阶段。这将允许在宽视场和全天空红外测量中识别PN。

This project will investigate techniques for the detection and characterization of planetary nebulae at infrared wavelengths. There are ~3,500 known PN in the Galaxy, with the majority discovered in recent years from Galactic Plane (GP) surveys at optical wavelengths, particularly in H-alpha (e.g. MASH -- Parker et al. 2006; IPHAS -- Sabin et al. 2014). Population estimates from models varyfrom ~6000 up to ~45000 depending on whether binarity is a requirement or whether single stars can also form PN. At the moment this is an open question in stellar evolution. There is now a move toIR detection techniques which are less prone to Galactic extinction and probe longer sightlines. This project will build on the UWISH2 survey, the first imaging survey of the northern GP in the v=1-0S(1) ro-vibrational line of molecular hydrogen (H2) at 2.12 microns (Froebrich et al. 2015), which resulted in the detection of ~300 PN candidates (b= +/- 1.5 degrees), with roughly 2/3 of these being new detections not seen in H-alpha and ~50% having bipolar morphology. The first phase of the project will be to reduce and publish long-slit K-band spectroscopy of a subset of these objects to further determine their PN nature (observations obtained July 2016 at WHT), with appropriate follow-up with Br-gamma and H2 line imaging (proposal submitted) and future possible IFS observations. In the second phase of the project, modelling of the recombination and molecular line emission spectra/images will be explored via PDR models, constrained by the observations (the student will attend the 2017 Cloudy workshop). The aim is to produce a suite of emission line and continuum modesl of PN in the IR as a function of evolutionary stage. This will then allow identification of PN in wide-field and all-sky IR surveys.