Tracing Gas from Bars to Nuclear Outflows: The Fermi Bubbles & Tilted Disk

Dhanesh Krishnarao被授予NSF天文学和天体物理学博士后奖学金，在约翰霍普金斯大学进行研究和教育计划。 Krishnarao将使用光谱线跟踪和研究银河系中心附近的高分辨率星际物质流。 他将观察从MW核发出的大型等离子体流出，称为费米泡，沿着MW棒的电离气体结构称为“倾斜盘”，以及低电离（核）发射区或LI（N）ER的银河系模拟物。 这项研究的结果将使天文学家能够了解从棒星系中心出现的气体和辐射如何影响其形成和演化，并将揭示LI（N）ER的起源。 在该项目的教育部分，Krishnarao将开发基于播客的音频课程，以促进小学和中学学生的科学探究，包括当地服务水平低下的社区的学生。使用威斯康星州H-Alpha Mapper，该研究项目将产生费米气泡和银河系棒中电离气体的第一个连续运动学地图。结合第五次斯隆数字巡天中现有的发射线和即将到来的吸收线观测，该项目将开发一种新的统计方法，以绘制在棒和费米泡背景下的盘-晕界面处的气体分布。最后，该项目将使用3D光电离建模与光学和紫外光谱，以开发一个新的理解LI（N）ER内MW bar.This奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

Dhanesh Krishnarao is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to conduct a program of research and education at Johns Hopkins University. Krishnarao will track and study the flow of interstellar matter at high resolution near the center of the Milky Way (MW) galaxy using optical spectral lines. He will observe large plasma outflows called Fermi Bubbles emanating from the MW nucleus, a structure of ionized gas called the “Tilted Disk” along the MW bar, and the Galactic analog of Low Ionization (Nuclear) Emission Regions or LI(N)ERs. Results from this study will allow astronomers to understand how gas and radiation emerging from the center of a barred galaxy influence its formation and evolution, and they will shed light on the origin of LI(N)ERs. For the education component of this project, Krishnarao will develop podcast-based audio courses to promote scientific inquiry in elementary and middle school students, including ones in local underserved communities.Using the Wisconsin H-Alpha Mapper, this research project will produce the first ever continuous kinematic map of ionized gas in the Fermi Bubbles and the bar of the Milky Way. Combining existing emission-line and upcoming absorption-line observations in the fifth Sloan Digital Sky Survey, the project will develop a new statistical method to map the gas distribution at the disk-halo interface within the context of the bar and Fermi Bubbles. Lastly, the project will use 3D photoionization modeling with optical and UV spectra to develop a new understanding of LI(N)ERs within the MW bar.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.