A sky survey of neutral Hydrogen at 21 cm using NARIT 4.5m small radio telescope

Abstract

We surveyed the neutral hydrogen (HI) at 21 cm by using the 4.5m Thai Small Radio Telescope (SRT) of the National Research Institute of Thailand (NARIT) during January-March 2019. The main aim of this project is for doing the distribution maps of HI in our Galaxy which will be shown in terms of the radial velocities and the HI positions in the galactic coordinate. The selected positions are mainly along the galactic plane (above or under the plane) within 21 degrees. The galactic longitudes are during 0 to 258 degrees. According to studies, the spectrum mode of NARIT-SRT receiver is recorded and divided into 400 channels with the velocity resolution ∼1.05 kms-1. Full width at half maximum (FWHM) of the NARIT-SRT is about 3-4 degrees. Its system temperature is 147.5 ± 5.1 K. The distribution map of HI clouds at 21 cm with the NARIT-SRT is presented in term of the radial velocity (vr ) in the range of [0: +220] kms-1 and the column density of HI down to the level 1019 per cm-2. Our results are in good agreement with theoretical values and international database.