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Full-Text Articles in Physics
Biases In Metallicity Measurements From Global Galaxy Spectra: The Effects Of Flux Weighting And Diffuse Ionized Gas Contamination, Ryan L. L. Sanders, Alice E. Shapley, Kai Zhang, Renbin Yan
Biases In Metallicity Measurements From Global Galaxy Spectra: The Effects Of Flux Weighting And Diffuse Ionized Gas Contamination, Ryan L. L. Sanders, Alice E. Shapley, Kai Zhang, Renbin Yan
Physics and Astronomy Faculty Publications
Galaxy metallicity scaling relations provide a powerful tool for understanding galaxy evolution, but obtaining unbiased global galaxy gas-phase oxygen abundances requires proper treatment of the various line-emitting sources within spectroscopic apertures. We present a model framework that treats galaxies as ensembles of H II and diffuse ionized gas (DIG) regions of varying metallicities. These models are based upon empirical relations between line ratios and electron temperature for H II regions, and DIG strong-line ratio relations from SDSS-IV MaNGA IFU data. Flux-weighting effects and DIG contamination can significantly affect properties inferred from global galaxy spectra, biasing metallicity estimates by more than …
The Carbon And Nitrogen Abundance Ratio In The Broad Line Region Of Tidal Disruption Events, Chenwei Yang, Tinggui Wang, Gary J. Ferland, Liming Dou, Hongyan Zhou, Ning Jiang, Zhenfeng Sheng
The Carbon And Nitrogen Abundance Ratio In The Broad Line Region Of Tidal Disruption Events, Chenwei Yang, Tinggui Wang, Gary J. Ferland, Liming Dou, Hongyan Zhou, Ning Jiang, Zhenfeng Sheng
Physics and Astronomy Faculty Publications
The rest-frame UV spectra of three recent tidal disruption events (TDEs), ASASSN-14li, PTF15af, and iPTF16fnl, display strong nitrogen emission lines but weak or undetectable carbon lines. In these three objects, the upper limits of the C III] λ1908/N III] λ1750 ratio are about two orders of magnitude lower than those of quasars, suggesting a high abundance ratio of [N/C]. With detailed photoionization simulations, we demonstrate that C2+ and N2+ are formed in the same zone, so the CIII]/N III] ratio depends only moderately on the physical conditions in the gas and weakly on the shape of …
Atomic Data Revisions For Transitions Relevant To Observations Of Interstellar, Circumgalactic, And Intergalactic Matter, Frances H. Cashman, Varsha P. Kulkarni, Romas Kisielius, Gary J. Ferland, Pavel Bogdanovich
Atomic Data Revisions For Transitions Relevant To Observations Of Interstellar, Circumgalactic, And Intergalactic Matter, Frances H. Cashman, Varsha P. Kulkarni, Romas Kisielius, Gary J. Ferland, Pavel Bogdanovich
Physics and Astronomy Faculty Publications
Measurements of element abundances in galaxies from astrophysical spectroscopy depend sensitively on the atomic data used. With the goal of making the latest atomic data accessible to the community, we present a compilation of selected atomic data for resonant absorption lines at wavelengths longward of 911.753 Å (the H I Lyman limit), for key heavy elements (heavier than atomic number 5) of astrophysical interest. In particular, we focus on the transitions of those ions that have been observed in the Milky Way interstellar medium (ISM), the circumgalactic medium (CGM) of the Milky Way and/or other galaxies, and the intergalactic medium …