Studying the Kinematics of the Neutral Gas in the Extraplanar of the Milky Way

Abstract

The study is based on the Parkes Galactic All Sky Survey (GASS III) to investigate the neutral hydrogen (H I) emission in the areas surrounding the disc of the Milky Way (MW). The aim of the study is to looking for a sign of disk-halo interaction by tracing the kinematics of the H I in different heights from the midplane of the MW, as a spiral galaxy. The analysis focused on the 21 cm spectral line to examine the shape of the emission line and determine the Gaussian parameters according to the number of fitting functions. Twelve positions were investigated by chosen two slices with longitude (l = 20̊, 340̊) and different latitude (b = 10̊, 12̊, 14̊, 16̊, 18̊, 20̊) for each slice. In some positions the line profiles show broadening or even line splitting as a result to interaction between different component with different kinematics and physical environments. Our results also indicate that the velocity reduces with increase the height from the midplane and take this as evidence of lags as a result to the interaction between the disk and halo.