%0 Generic %1 cowie2015luminosity %A Cowie, Lennox L. %A Barger, Amy J. %A Songaila, Antoinette %D 2015 %K diagnostics emission lines metallicity %T Luminosity Dependence and Redshift Evolution of Strong Emission-line Diagnostics in Star-Forming Galaxies %U http://arxiv.org/abs/1512.00017 %X We examine the redshift evolution of standard strong emission-line diagnostics for Hbeta-selected star-forming galaxies using the local SDSS sample and a new z = 0.2 - 2.3 sample obtained from HST WFC3 grism and Keck DEIMOS and MOSFIRE data. We use the SDSS galaxies to show that there is a systematic dependence of the strong emission-line properties on Balmer-line luminosity, which we interpret as showing that both the N/O abundance and the ionization parameter increase with increasing line luminosity. Allowing for the luminosity dependence tightens the diagnostic diagrams and the metallicity calibrations. The combined SDSS and high-redshift samples show that there is no redshift evolution in the line properties once the luminosity correction is applied, i.e., all galaxies with a given L(Hbeta) have similar strong emission-line distributions at all the observed redshifts. We argue that the best metal diagnostic for the high-redshift galaxies may be a luminosity-adjusted version of the NII6584/Halpha metallicity relation.

@misc{cowie2015luminosity, abstract = {We examine the redshift evolution of standard strong emission-line diagnostics for Hbeta-selected star-forming galaxies using the local SDSS sample and a new z = 0.2 - 2.3 sample obtained from HST WFC3 grism and Keck DEIMOS and MOSFIRE data. We use the SDSS galaxies to show that there is a systematic dependence of the strong emission-line properties on Balmer-line luminosity, which we interpret as showing that both the N/O abundance and the ionization parameter increase with increasing line luminosity. Allowing for the luminosity dependence tightens the diagnostic diagrams and the metallicity calibrations. The combined SDSS and high-redshift samples show that there is no redshift evolution in the line properties once the luminosity correction is applied, i.e., all galaxies with a given L(Hbeta) have similar strong emission-line distributions at all the observed redshifts. We argue that the best metal diagnostic for the high-redshift galaxies may be a luminosity-adjusted version of the [NII]6584/Halpha metallicity relation.}, added-at = {2015-12-02T10:50:13.000+0100}, author = {Cowie, Lennox L. and Barger, Amy J. and Songaila, Antoinette}, biburl = {https://www.bibsonomy.org/bibtex/269678b93cdb9a38ff7065468966f769b/miki}, description = {[1512.00017] Luminosity Dependence and Redshift Evolution of Strong Emission-line Diagnostics in Star-Forming Galaxies}, interhash = {69f072c1c305daff40d6e2bdf42a1754}, intrahash = {69678b93cdb9a38ff7065468966f769b}, keywords = {diagnostics emission lines metallicity}, note = {cite arxiv:1512.00017Comment: Accepted for publication in ApJ. 16 pages, 15 figures}, timestamp = {2015-12-02T10:50:13.000+0100}, title = {Luminosity Dependence and Redshift Evolution of Strong Emission-line Diagnostics in Star-Forming Galaxies}, url = {http://arxiv.org/abs/1512.00017}, year = 2015 }