Galactic H emission line studies using DEFPOS at the TÜBİTAK National Observatory

Authors : Muhittin ŞAHAN

Pages : 242-253

View : 19 | Download : 6

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :  H α ` role=`presentation`> α α \alpha spectral line insert ignore into journalissuearticles values(6563 Å); profiles of eight northern H II regions in our galaxy insert ignore into journalissuearticles values(Sh2-25, Sh2-131, Sh2-237, IC 434, IC 1318, NGC 1982, NGC 6543, and NGC 6611); have been obtained using the Dual Etalon Fabry-Pérot Optical spectrometer insert ignore into journalissuearticles values(DEFPOS); with a 4` field of view, located at the coudé focus of the 150 cm RTT150 telescope at the TÜBİTAK National Observatory insert ignore into journalissuearticles values(TUG, Antalya, Turkey);. Observations were carried out during the nights of 25-27 December 2015 and 6-7 June 2017 with different long exposure times ranging from 900 s to 3600 s. These spectra provide information about the local standard of rest insert ignore into journalissuearticles values(LSR); velocities, the full width at half maximum insert ignore into journalissuearticles values(FWHM);, and densities of the sources. The LSR velocities and the FWHM of the H α ` role=`presentation`> α α \alpha emission lines were found to be in the range of -50.31 km/s to 27.57 km/s and 34.88 km/s to 44.54 km/s insert ignore into journalissuearticles values(mean FWHM: 37.19 km/s);, respectively. The NGC 6543 insert ignore into journalissuearticles values(Cat`s Eye Nebula); is the faintest one insert ignore into journalissuearticles values(75.06 R);, while the NGC 1982 H II region is brightest source insert ignore into journalissuearticles values(38,477.3 R);. The LSR velocity and the FWHM results of the DEFPOS/RTT150 system were compared with the data by several authors given in the literature and the results of DEFPOS data were found to be in good agreement with data given in the literature. Since there is not enough information on LSR velocities and intensities of such galactic sources with low angular size in the literature, we believe that this spectrometer will provide a powerful tool for the study of diffuse ionized gas and these new results may have significant contributions to the literature. In the future, we are planning to prepare H α ` role=`presentation`> α α \alpha maps with the 4` field of view of some diffuse ionized emission sources selected from VTSS and WHAM H α ` role=`presentation`> α α \alpha maps with large fields of view.
Keywords : ISM H II regions, emission nebulae, planetary nebulae, open clusters, techniques spectroscopic, Fabry Perot, radial velocities, line widths