GBT22B-330

SIP: Characterizing the Partially Ionized Medium around HII Regions

Abstract

The partially ionized medium (PIM) is an elusive component of the interstellar medium which has been observed as narrow hydrogen radio recombination lines (H0RRLs) around HII regions. In this project we aim to characterize the properties of the PIM towards NGC2024 and W3, where its emission has been detected, and to explore the use of multi-frequency observations to confirm a tentative detection towards Orion A. Through these observations we will determine the density and size scales of the PIM, and through these, determine its ionizing mechanism towards these regions. The results and methods derived from this project will inform the interpretation of future H0RRL observations. These project will also produce a wealth of radio recombination lines (C, S and He), and molecular lines (CH, OH, methanol) that will be used to study the cold neutral and warm ionized gases in and around the HII regions.

Investigators

Name	Institution
Pedro Salas *	Green Bank Observatory
Kimberly Emig	National Radio Astronomy Observatory
Loren Anderson	West Virginia University
Anish Roshi	Florida, University of Central

* indicates the PI