The electron temperatures of SDSS high-metallicity giant extragalactic HII regions - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




The electron temperatures of SDSS high-metallicity giant extragalactic HII regions - Astrophysics > Cosmology and Nongalactic Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: Spectra of high-metallicity 12+logO-H > 8.2 HII regions where oxygenauroral lines are measurable in both the O+ and O++ zones, have been extractedfrom the Data Release 6 of the Sloan Digital Sky Survey SDSS. Our finalsample consists of 181 SDSS spectra of HII regions in galaxies in the redshiftrange from ~0.025 to ~0.17. The t 2,O-t 3,O diagram is examined. In the SDSSHII regions, the electron temperature t 2,O is found to have a large scatter ata given value of the electron temperature t 3,O. The majority of the SDSS HIIregions lie below the t 2,O-t 3,O relation derived for HII regions in nearbygalaxies, i.e. the positions of the SDSS HII regions show a systematic shifttowards lower t 2,O temperatures or-and towards higher t 3,O temperatures. Thescatter and shift of the SDSS HII regions in the t 2,O-t 3,O diagram can beunderstood if they are composite nebulae excited by two or more ionizingsources of different temperatures.



Author: L.S.Pilyugin, J.M.Vilchez, B.Cedres, T.X.Thuan

Source: https://arxiv.org/







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