Gaussian deconvolution of 21 cm HI spectra

Abstract

This work investigates atomic hydrogen emission line spectra at 1420 MHz from the 100 meter Green Bank Telescope in Green Bank, West Virginia using the technique of Gaussian deconvolution. Data from the Green Bank Telescope is superior to data previously used in Gaussian deconvolution studies as the Green Bank Telescope minimizes side lobe radiation, producing some of the purest 21 cm spectra to date. The results show evidence for the components of the Cold Neutral Medium, Warm Neutral Medium, and a third, broad component previously hypothesized to be due to instrumental effects. The nature of the broad component is discussed, and we conclude that the broad component can be produced by a combination of Cold and Warm Neutral Medium emission regions, and Galactic streaming and noncircular motions.