• DOI:10.1111/j.1365-2966.2011.18389.x
• Corpus ID: 53532689

Abundance determination of multiple star-forming regions in the H II galaxy SDSS J165712.75+321141.4

@article{Hagele2011AbundanceDO,
  title={Abundance determination of multiple star-forming regions in the H II galaxy SDSS J165712.75+321141.4},
  author={Guillermo F. Hagele and Rub{\'e}n Garc{\'i}a-Benito and Enrique P{\'e}rez-Montero and {\'A}ngeles I. D́ıaz and M V Cardaci and Ver{\'o}nica Firpo and Elena Terlevich and Roberto Terlevich},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2011},
  volume={414},
  pages={272-288}
}

• G. Hagele, R. García-Benito, +5 authors R. Terlevich
• Published 21 January 2011
• Physics
• Monthly Notices of the Royal Astronomical Society

We analyze high signal-to-noise spectrophotometric observations acquired simul- taneously with TWIN, a double-arm spectrograph, from 3400 to 10400u of three star-forming regions in the Hii galaxy SDSS J165712.75+321141.4. We have measured four line temperatures: Te((Oiii)), Te((Siii)), Te((Oii)), and Te((Sii)), with high preci- sion, rms errors of order 2%, 5%, 6% and 6%, respectively, for the brightest region, and slightly worse for the other two. The temperature measurements allowed the direct derivation of ionic abundances of oxygen, sulphur, nitrogen, neon and argon. We have computed CLOUDY tailor-made models which reproduce the O 2+ mea- sured thermal and ionic structures within the errors in the three knots, with deviations of only 0.1 dex in the case of O + and S 2+ ionic abundances. In the case of the electron temperature and the ionic abundances of S + /H + , we find major discrepancies which could be consequence of the presence of colder diffuse gas. The star formation history derived using STARLIGHT shows a similar age distribution of the ionizing popula- tion among the three star-forming regions. This fact suggests a similar evolutionary history which is probably related to a process of interaction with a companion galaxy that triggered the star formation in the different regions almost at the same time. The hardness of the radiation field mapped through the use of the softness parame- teris the same within the observational errors for all three regions, implying that the equivalent effective temperature of the radiation fields are very similar for all the studied regions of the galaxy, in spite of some small differences in the ionization state of different elements. Regarding the kinematics of the galaxy, the gas rotation curve shows a deviation from the circular motion probably due either to an interaction process or related to an expanding bubble or shell of ionized gas approaching us. A dynamical mass of 2.5×10 10 Mis derived from the rotation curve.