Abstract
DEFPOS Fabry–Perot spectrometer, located at the coude exit of the RTT-150 telescope (Bakirlitepe, Antalya, Turkey), has been used to measure the ionized gas within the Lagoon Nebula (M 8) which is an H II region (Sh2-25). Eighty-four H \(\alpha\) emission line spectra obtained from the H II region provide detailed information about some physical properties of the gas surrounding the H II region. The line widths, \(V_{\textrm{LSR}}\) velocities, and \({I_{\textrm{ H}{\alpha}}}\) intensities of the H \(\alpha\) emission spectra were found to be in the range from \(27.5\pm 5.80\) to \(41.50\pm 1.99\) km s \({}^{-1}\) (mean \(35.50\pm 2.05\) km s \({}^{-1}\) ), \(-13.67\pm 0.58\) and \(3.19\pm 0.72\) km s \({}^{-1}\) (mean \(-4.92\pm 0.32\) km s \({}^{-1}\) ), and \(173.35\pm 9.97\) R and \(13834.20\pm 21.56\) R (mean \(2247.65\pm 8.33\) R), respectively. The mean LSR velocity and line width of the nebula were also compared with previous works. Since there is not enough information on intensities and LSR velocities of such galactic sources with low angular size in the literature, we believe that DEFPOS spectrometer will provide a powerful tool for the study of the diffuse ionized gas, and these new results may have significant contributions to the literature.
