Oxygen and helium abundances in Galactic H ii regions — II. Abundance gradients

By L. Deharveng, M. Peña, J. Caplan, R. Costero. 2000

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The absolute integrated fluxes that we obtained (Paper I) for 34 H ii regions, with Galactocentric distances RG in the 6.6–17.7 kpc range, in the emission lines [O ii] λλ3726 and 3729, [O iii] λλ4363 and 5007, He iλ5876, Hα and Hβ, are analysed to derive the extinctions, the electron densities and temperatures, the ionic abundances O+/H+, O++/H+ and He+/H+ and the O/H abundances. The electron temperature has been derived from the [O iii] λ4363/λ5007 ratio in six H ii regions with RG between 6.6 and 14.8 kpc. These new measurements of Te, which are in good agreement with those from radio recombination lines, widen the RG range for which reliable Te measurements exist. Combining our new Te([O iii]) results with the radio values, we obtain the following temperature relationship: TeK]=(372±38)RG+4260±350. The O+/H+ and O++/H+ abundances have been obtained assuming a two-temperature H ii region model. Our O/H relationship for 5 kpc<RG<15 kpc is 12+log O/H= (−3.95±0.49)×10−2RG+(8.82±0.05). The slope is lower, by a factor of 2, than that previously obtained by Shaver et al. No significant flattening of this relation is obtained out to 15 kpc. At the solar Galactocentric distance, 12+log(O/H)=8.48, in good agreement with the O/H abundance measured in the local interstellar medium by Meyer et al., and a factor of 2 lower than the solar abundance. Our helium observations show that even a region ionized by a star earlier than O6.5 may contain a significant amount of neutral helium. We confirm the high ΔY/Δ(O/H) value (≥180) measured in the Galaxy by Peimbert et al.

Subfields: Astronomy and Astrophysics, Atmospheric Science

View Paper: https://www.semanticscholar.org/paper/dc62e1491212ce31cd4487081d0e6ce410fd6486

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Citations in the corpus

OXYGEN ABUNDANCES IN NEARBY FGK STARS AND THE GALACTIC CHEMICAL EVOLUTION OF THE LOCAL DISK AND HALO (2013, background): “Present-day elemental abundance gradients with Galactocentric distance for both oxygen and iron have been observed (e.g., Deharveng et al. 2000; Friel et al. 2002; Jacobson et al. 2007; Henry et al. 2010), implying that radial migration provides a way to explain the range of elemental abundances…”
Physical Processes in the Interstellar Medium (2014, methodology): “…of the optical emission lines of Oii and Oiii together with Hα and Hβ can be used to constrain the oxygen abundance in Galactic Hii regions (see e.g. Deharveng et al., 2000), from which the total metallicity Z follows if we assume that the oxygen abundance scales linearly with Z. Alternatively,…”
Abundance Gradients in the Galaxy (2006, methodology): “Deharveng et al. (2000) determined oxygen abundances for 34 H ii regions observed in the optical and presented by Caplan et al. (2000).”
The Composition Gradient in M101 Revisited. II. Electron Temperatures and Implications for the Nebular Abundance Scale (2003, methodology): “Likewise, measurements of radio recombination line temperatures of Galactic H ii regions give results that are consistent with forbidden line measurements of the same objects (Shaver et al. 1983; Deharveng et al. 2000).”
EXTRAGALACTIC CHEMICAL ABUNDANCES: DO H ii REGIONS AND YOUNG STARS TELL THE SAME STORY? THE CASE OF THE SPIRAL GALAXY NGC 300 (2009, methodology): “This value can be compared to the results obtained for other galaxies, such as M33, where Magrini et al. (2007) measured 570± 130 K kpc−1, and the Milky Way, for which Deharveng et al. (2000) found 372± 38 K kpc−1 from hydrogen radio recombination lines (a flatter slope, 287± 46 K kpc−1, was obtaine”
The Chemical Composition of the Small Magellanic Cloud H II Region NGC 346 and the Primordial Helium Abundance (2000, background): “…to determine the helium abundance because among the brightest galactic H ii regions it is the one with the highest degree of ionization and consequently with the smallest correction for the presence of He0 (i.e. ICF (He) is very close to unity e. g. Peimbert et al. 1992; Deharveng et al. 2000).”
Abundance Gradients and the Formation of the Milky Way (2001, methodology): “Deharveng et al. (2000) analyzed a new sample of 34 H II regions located between 6.6 and 17.7 kpcs from the Galactic center and after a careful estimate of the electron temperatures in those objects they obtained, using their best observations, an oxygen abundance gradient which is Ñatter (by a…”
THE SPATIALLY RESOLVED STAR FORMATION LAW FROM INTEGRAL FIELD SPECTROSCOPY: VIRUS-P OBSERVATIONS OF NGC 5194 (2009, background): “…in NGC 5194 11 gen abundance and the oxygen abundance in Milky Way H II regions (Grevesse et al. 1996; Allende Prieto et al. 2001; Shaver et al. 1983; Deharveng et al. 2000), it can be seen in Figure 9 that using a factor of 1.5 implies that the brightest Hα emitting regions in NGC 5194 are…”
Using Cepheids to determine the galactic abundance gradient I. The solar neighbourhood (2001, result): “The same results were also reported by Deharveng et al. (2000).”
A UNIFIED REPRESENTATION OF GAS-PHASE ELEMENT DEPLETIONS IN THE INTERSTELLAR MEDIUM (2009, background): “…distance RGC that ranges from about −0.03 to −0.10 dex kpc −1 (Shaver et al. 1983; Afflerbach, Churchwell, & Werner 1997; Gummershach et al. 1998; Deharveng et al. 2000; Martins & Viegas 2000; Rolleston et al. 2000; Giveon et al. 2002; Mart́ın-Hernández et al. 2002; Luck, Kovtyukh, &…”
On the oxygen abundance determination in HII regions. - High-metallicity regions (2001, methodology): “Following Deharveng et al. (2000) all the heavily reddened HII regions were excluded from consideration.”
Interstellar Turbulence II: Implications and Effects (2004, background): “…& Lambert 1994) and clusters (Rolleston et al. 1994); the Magellanic clouds (e.g., Olszewski et al. 1991); the ISM (Meyer et al. 1998); Galactic H II regions (Deharveng et al. 2000) and H II regions in disk (see review in Henry & Worthey 1999) and dwarf-irregular galaxies (e.g., Thuan et al. 1995).”
Abundances of Metal-rich H II Regions in M51 (2004, background): “The sample of objects shown includes, besides the M51 HII regions studied here, a number of nebulae extracted from the literature (Kennicutt et al. 2003; Garnett et al. 1997; van Zee et al. 1998; Deharveng et al. 2000; Díaz & Pérez-Montero 2000; Díaz et al. 2000; Castellanos et al. 2002).”