DEFPOS H alpha observations of HII regions

Aksaker N., ŞAHAN M., Yegingil I., EMRAHOĞLU N.

NEW ASTRONOMY, vol.16, no.8, pp.485-491, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 16 Issue: 8
  • Publication Date: 2011
  • Doi Number: 10.1016/j.newast.2011.04.005
  • Journal Name: NEW ASTRONOMY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.485-491
  • Keywords: Instrumentation: interferometers, ISM: HII regions, Techniques: radial velocities, Techniques: interferometric, II REGIONS, INTENSITY RATIOS, NORTHERN SKY, MILKY-WAY, EMISSION, HYDROGEN, INSTRUMENTATION, WHAM
  • Middle East Technical University Affiliated: Yes


We present H alpha emission line measurements of northern bright HII regions selected from the Sharpless (1959) catalog near the Galactic plane (b <= +/- 6 degrees). A total of 10 HII regions were observed with DEFPOS (Dual Etalon Fabry-Perot Optical Spectrometer) system at the f/48 Coude focus of 150 cm RT1150 telescope located at TUBITAK National Observatory (TUG) in Antalya/Turkey. The intensities, the local standard of rest (LSR) velocities (V-LSR), and the linewidths (Full Width Half Maximum: FWHM) of the H alpha emission line from our observations were in the range of 84 to 745 Rayleigh (R [one Rayleigh (R) is 10(6)/4 pi photons cm(-2) sr(-1) s(-1) = 2.4110(-7) erg cm(-2) sr(-1) s(-1) at H alpha and corresponds to an emission measure (EM = integral n(e)(2)dl) of 2.3 pc cm(-6) for a gas temperature of 8000K, where n(e) is the averaged electron density within an emitting region in the interstellar medium; dl is distance element to the source region (Haffner et al., 2003; Reynolds et al., 2005), 3 to -43 km s(-1) and 30 to 73 km s(-1), respectively. The LSR velocities and the linewidths from the data were obtained and compared with early results. We found that our results are in close agreement with them. Moreover, associated stars of some of the HII regions were updated by analyzing their location, velocities, and brightness. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.