GBT24B-101

Ionization State of the Warm Ionized Medium in the Inner Galaxy

Abstract

The Warm Ionized Medium (WIM) consists of diffuse ionized gas in the
Galactic mid-plane and is the last major component of the interstellar
medium to be studied at high angular and spectral resolution. OB-type
stars, with a scale height of 30pc, are thought to be the main source
of ionization. But hot low-mass evolved stars (UV stars), with a
scale height of 800pc, may significantly contribute to the WIM. Here,
we investigate the importance of UV stars by determining the hardness
of the radiation field as a function of Galactic latitude. To do this
we request observations of radio recombination lines (RRLs) with the
GBT and forbidden lines of Ne, Ar, and S with the JWST at two Galactic
latitudes, G20.0+0.0 and G20.0+0.6. These data will be used to
constrain the radiation field using CLOUDY simulations that will allow
us to evaluate the importance of UV stars.

Investigators

Name	Institution
GBT Operator	Green Bank Observatory
Dana Balser *	National Radio Astronomy Observatory
Tom Bania	Boston University
Loren Anderson	West Virginia University
Trey Wenger	Wisconsin at Madison, University of
Matteo Luisi	Westminster College

* indicates the PI