A CLASSIFICATION OF H II REGIONS BASED ON OXYGEN AND HELIUM LINES: THE CASES OF TOL 2146-391 AND TOL 0357-3915
- Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-264, Mexico CP 04510, DF (Mexico)
We present long-slit spectrophotometry of two H II galaxies: TOL 2146-391 and TOL 0357-3915. We performed a detailed analysis that involves abundance determinations relaxing the assumption of homogeneous temperature. The temperature inhomogeneity values, t{sup 2}, were obtained through two methods: (1) comparing abundances from oxygen recombination lines to abundances from collisionally excited lines and (2) by using the line intensity ratios of a set of He I lines together with the HELIO10 program. We find that the HELIO10 program is a good alternative to obtain a t{sup 2} value in photoionized regions where recombination lines of heavy elements are not available. We have plotted 27 high- and low-metallicity H II regions in an oxygen degree of ionization versus t{sup 2} diagram; we find areas populated by H II regions and areas void of them; the physical characteristics of each area are discussed. In addition, an average t{sup 2} value can be determined for the objects in each area. We propose to use this (t{sup 2}) value for the cases where a direct measurement of t{sup 2} cannot be determined.
- OSTI ID:
- 22036948
- Journal Information:
- Astrophysical Journal, Vol. 753, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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