Linking Galactic and Extragalactic Star Formation

令人惊讶的是，与宇宙中的其他星系相比，我们对银河系中全球恒星形成的了解如此之少。这是因为太阳位于平坦的银河系圆盘中，而且几乎所有恒星的形成都发生在这个圆盘中。从天空看去，这个圆盘看起来像一个相对较薄的带，所有距离的恒星都在这个带内。这个项目将把这条光带分解成一张三维地图，目的是了解我们银河系中的全球恒星形成。这张地图将允许我们区分区域的亮度(一个观察到的属性)和它们的亮度(一个固有属性)。该团队将通过测量所有已知大质量恒星形成区在红外和射电波长下的亮度来创建三维地图，并将使用射电观测将红外和射电亮度转换为光度。当地的高中生将协助观察，为西弗吉尼亚州的学生提供重要的研究机会。PI和他的学生将把导出的光度分布与其他星系的分布进行比较，以确定我们生活的星系类型。他们还将估计我们银河系正在形成的恒星数量。这些结果将帮助我们更好地了解银河系中恒星的形成。由于没有完整的银河系恒星形成区域样本可以与外部星系的恒星形成区域进行比较，银河系和银河系外天文学家之间严重缺乏沟通。该团队将通过使用射电复合线观测创建一个由单个O星电离的所有银河系HII区域的星表来解决这个问题。当地的高中生将帮助观察，为西弗吉尼亚州的学生提供重要的科学机会。这些观测将使我们能够使用旋转曲线模型计算与观测到的径向速度的运动距离。该团队将通过定位具有相似径向速度和假定相似距离的HII区域集群来补充距离，并将使用人口合成模型针对目录偏差进行调整。PI和他的学生将计算出波长从8微米到21厘米的HII区域通量，并使用星表距离将这些通量转换为光度。他们将调查在HII区光度函数(LF)研究中发现的三个银河系外结果：在一些星系中看到的银河系LF的断裂，发现“簇状”和“分布”的HII区LF具有不同的形状，以及星系的LF形状与其哈勃类型之间的关联。然后，可以通过将所有星表HII区域的光度相加来计算银河系的总光度。然后，使用河外恒星形成速率校准，将银河系的总光度转换为恒星形成速率。

It is surprising how little we know about global star formation in our Milky Way Galaxy compared to other galaxies in the Universe. This is because the Sun lies in the flat Milky Way disk and because nearly all star formation occurs within this disk. Looking at the sky, the disk appears as a relatively thin band, with stars at all distances found within this band. This project will disentangle this band of light into a three-dimensional map with the aim of understanding the global star formation in our Galaxy. This map will allow us to differentiate between the brightness of regions (an observed property) with their luminosities (an intrinsic property). The team will create the three-dimensional map by measuring the brightness of all known massive star formation regions at infrared and radio wavelengths, and will use radio observations to turn the infrared and radio brightnesses into luminosities. Local high school students will assist in the observations, providing vital research opportunities for the students of West Virginia. The PI and his students will compare the distribution of derived luminosities with that of other galaxies to determine the type of galaxy we live in. They will also estimate how many stars our Galaxy is forming. These results will help us to better understand star formation in our Galactic home.There is a severe lack of communication between Galactic and extragalactic astronomers because there is no complete sample of Galactic star forming regions that can be compared to those of external galaxies. The team will solve this problem by creating a catalog of all Galactic HII regions ionized by single O-stars using radio recombination line observations. Local high school students will help with the observations, providing vital science opportunities for the students of West Virginia. These observations will allow us to compute kinematic distances from the observed radial velocities using a rotation curve model. The team will supplement the distances by locating clusters of HII regions that have similar radial velocities, and presumably similar distances, and will adjust for catalog biases using a population synthesis model. The PI and his students will derive HII region fluxes at wavelengths from 8 micron to 21 cm and turn these fluxes into luminosities using the catalog distances. They will investigate three extragalactic results found in studies of the HII region luminosity function (LF): the break in the Galactic LF seen in some galaxies, the finding that ''clustered'' and ''distributed'' HII-region LFs have different shapes, and the correlation between the galaxy's LF shape and its Hubble type. The total Milky Way luminosity can then be computed by summing the luminosities of all catalog HII regions. The total Milky Way luminosities will then be converted into star formation rates using extragalactic star formation rate calibrations.