The O/H Distribution in the Low-Mass Galaxies NGC 2366 and NGC 4395
1996; IOP Publishing; Volume: 460; Linguagem: Inglês
10.1086/176968
ISSN1538-4357
AutoresJean-René Roy, Julien Belley, Yvan Dutil, Pierre Martin,
Tópico(s)Gamma-ray bursts and supernovae
Resumoview Abstract Citations (63) References (75) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The O/H Distribution in the Low-Mass Galaxies NGC 2366 and NGC 4395 Roy, Jean-Rene ; Belley, Julien ; Dutil, Yvan ; Martin, Pierre Abstract Results of a spectrophotometric survey in the magellanic barred galaxy NGC 2366 and in the small weakly barred spiral galaxy NGC 4395, employing imaging spectrophotometry with narrow-band interference filters in the lines of Hα, Hβ, [O III] λ5007 and [N II] λ6584, are presented. The use of [O III]/Hβ as an abundance indicator is assessed; it is shown that for the probable range of the physical properties of the H II regions in NGC 2366 and NGC 4395, [O III]/Hβ may not give reliable estimates of O/H abundances in the interstellar gas in these two low-mass galaxies. Instead we use [NII]/[O III], which is more dependable at relatively low abundances. The derived mean levels of O/H (+/-1 σ dispersion) in NGC 2366 and NGC 4395 are 12 + log O/H = 8.19 +/- 0.14 and 8.33 +/- 0.25, respectively; the global gradients of both galaxies are flat. Mechanisms which could explain the absence of abundance gradients in low-mass and irregular galaxies are explored. Publication: The Astrophysical Journal Pub Date: March 1996 DOI: 10.1086/176968 Bibcode: 1996ApJ...460..284R Keywords: GALAXIES: ABUNDANCES; GALAXIES: INDIVIDUAL NGC NUMBER: NGC 2366; GALAXIES: INDIVIDUAL NGC NUMBER: NGC 4395; GALAXIES: ISM; ISM: H II REGIONS full text sources ADS | data products NED (138) SIMBAD (10)
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