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http://inaoe.repositorioinstitucional.mx/jspui/handle/1009/1000| The localized chemical pollution in NGC 5253 revisited: results from deep echelle spectrophotometry¹ | |
| Monica Rodriguez | |
| Acceso Abierto | |
| Atribución-NoComercial-SinDerivadas | |
| We present echelle spectrophotometry of the blue compact dwarf galaxy NGC 5253 obtained with the VLT UVES. We have measured the intensities of a large number of permitted and forbidden emission lines in four zones of the central part of the galaxy.We detect faint C ɪɪ and O ɪɪ recombination lines, the first time that these are unambiguously detected in a dwarf starburst galaxy. The physical conditions of the ionized gas have been derived using a large number of different line intensity ratios. Chemical abundances of He, N, O, Ne, S, Cl, Ar, and Fe have been determined following standard methods. C⁺⁺ and O⁺⁺ abundances have been derived from pure recombination lines and are larger than those obtained from collisionally excited lines (from 0.30 to 0.40 dex for C⁺⁺ and from 0.19 to 0.28 dex for O⁺⁺). This result is consistent with a temperature fluctuation parameter (t²) between 0.050 and 0.072.We confirm previous results that indicate the presence of a localized N enrichment in certain zones of NGC 5253 and detect a possible slight He overabundance in the same zones. The enrichment pattern agrees with that expected for the pollution by the ejecta ofWolf-Rayet (W-R) stars. The amount of enriched material needed to produce the observed overabundance is consistent with the mass lost by the number ofW-R stars estimated in the starbursts.We discuss the possible origin of the difference between abundances derived from recombination and collisionally excited lines (the so-called abundance discrepancy problem) in H ɪɪ regions, finding that a recent hypothesis based on the delayed enrichment by SN ejecta inclusions seems not to explain the observed features. | |
| The astrophysical journal | |
| 2007 | |
| Artículo | |
| Inglés | |
| Estudiantes Investigadores Público en general | |
| López Sánchez, Angel R.. et al., (2007). The localized chemical pollution in NGC 5253 revisited: results from deep echelle spectrophotometry¹, The Astrophysical journal, Vol.656(1): 168-185 | |
| ASTRONOMÍA Y ASTROFÍSICA | |
| Versión aceptada | |
| acceptedVersion - Versión aceptada | |
| Aparece en las colecciones: | Artículos de Astrofísica |
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