• M. Sahan

      Articles written in Journal of Astrophysics and Astronomy

    • The Eighty Six Hα Spectra from the Orion Nebula (M42, Sh2-281) with DEFPOS

      M. Sahan I. Yegingil

      More Details Abstract Fulltext PDF

      In this study, eighty six Hα (6563 Å) emission line spectra from the central region (∼40′×40′) of the Orion Nebula (NGC1976, M42, Sh2-281) have been obtained using DEFPOS spectrometer with a circular field of view of 4′ at TUBITAK National Observatory (TUG, Antalya, Turkey). Measurements provide information about the intensities, line widths, and radial velocities of the gas surrounding the Sh2-281 HII-region. The intensities, the radial velocities and the line widths of the Hα emission line were found in the range of from 319.85 R to 6009.08 R (mean 2006 ± 400 R), from −14.91 km s−1 to +5.40 km s−1 (mean −4.51 ± 3.80 km s−1), and from 27.83 km s−1 to 49.60 km s−1 (mean 41.09 ± 7.74 km s−1), respectively. Moreover, the mean emission measure (EM) calculated from I values was obtained as 4513.02 cm−6 pc. The mean LSR velocity of the nebula was found to be −4.51 km s−1 and was compared with some previous works. The intensity values of DEFPOS data were also compared with the data obtained from VTSS, SkyView, and SHASSA maps using APER and SKY codes. We found that our results were approximately the similar variation with VTSS (mean 2002.04 R), SkyView (mean 2680.05 R), and SHASSA (mean 2400.06 R) maps. We believe that DEFPOS spectrometer with a 4′ diameter field of view is able to provide a powerful tool for the study of diffuse ionized gas and this new results may have significant contribution to the literature.

  • Journal of Astrophysics and Astronomy | News

    • Continuous Article Publication

      Posted on January 27, 2016

      Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2017-2019 Indian Academy of Sciences, Bengaluru.