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

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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.