Nebular Continuum and Line Emission in Stellar Population Synthesis Models

2016/11/24 by Nell Byler, Julianne J. Dalcanton, Charlie Conroy +1 · 406 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Line (geometry) #Photoionization #Population #Star formation #Stars #Stellar atmosphere #Stellar population #astro-ph.GA

paper · pdf · doi:10.3847/1538-4357/aa6c66

published in The Astrophysical Journal 840(1), 44 (IOP Publishing) · 35 pages, 29 figures

arxiv created 2016/11/24 · openalex created_date 2016/12/08 · openalex publication_date 2017/05/01 · arxiv updated 2017/05/10 · openalex updated_date 2026/08/08

Abstract

Abstract Accounting for nebular emission when modeling galaxy spectral energy distributions (SEDs) is important, as both line and continuum emissions can contribute significantly to the total observed flux. In this work, we present a new nebular emission model integrated within the Flexible Stellar Population Synthesis code that computes the line and continuum emission for complex stellar populations using the photoionization code Cloudy . The self-consistent coupling of the nebular emission to the matched ionizing spectrum produces emission line intensities that correctly scale with the stellar population as a function of age and metallicity. This more complete model of galaxy SEDs will improve estimates of global gas properties derived with diagnostic diagrams, star formation rates based on H α , and physical properties derived from broadband photometry. Our models agree well with results from other photoionization models and are able to reproduce observed emission from H ii regions and star-forming galaxies. Our models show improved agreement with the observed H ii regions in the Ne iii /O ii plane and show satisfactory agreement with He ii emission from z = 2 galaxies, when including rotating stellar models. Models including post-asymptotic giant branch stars are able to reproduce line ratios consistent with low-ionization emission regions. The models are integrated into current versions of FSPS and include self-consistent nebular emission predictions for MIST and Padova+Geneva evolutionary tracks.

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Cited by

• Extreme Neutral Outflow in a non-AGN Quiescent Galaxy at z~1.3
• Stellar, Gas, and Dust Emission of Star-forming Galaxies out to z ∼ 2
• Oxyster: A Circumgalactic Low-ionization Oxygen Nebula next to a Starburst Galaxy at z∼1