NEBULAR: A simple synthesis code for the hydrogen and helium nebular spectrum

Abstract

NEBULAR is a lightweight code to synthesize the spectrum of an ideal, mixed hydrogen and helium gas in ionization equilibrium, over a useful range of densities, temperatures and wavelengths. Free-free, free-bound and two-photon continua are included as well as parts of the HI, HeI and HeII line series. NEBULAR interpolates over publicly available data tables; it can be used to easily extract information from these tables without prior knowledge about their data structure. The resulting spectra can be used to e.g. determine equivalent line widths, constrain the contribution of the nebular continuum to a bandpass, and for educational purposes. NEBULAR can resample the spectrum on a user-defined wavelength grid for direct comparison with an observed spectrum; however, it can not be used to fit an observed spectrum.

arXiv commentMajor revision, 14 pages, 5 figures, 5 tables, accepted for publication in PASP. Fixed typos and errors, added a section about software verification. Plots have been moved to the Appendix, including the NEBULAR syntax used to create the corresponding data

References in corpus (11)

• Galaxy Zoo : 'Hanny's Voorwerp', a quasar light echo?
• Improved He I Emissivities in the Case B Approximation
• Corrigendum: Improved He~I Emissivities in the Case B Approximation
• Accurate determination of the free-free Gaunt factor; I - non-relativistic Gaunt factors
• Two-photon transitions in primordial hydrogen recombination
• Theoretical calculations of the HI, HeI and HeII free-bound continuou emission spectra
• Angular momentum changing transitions in proton-Rydberg atom collisions
• The Continuum Emission Spectrum of Hf 2-2 near the Balmer Limit and the ORL versus CEL abundance and temperature Discrepancy
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Cited by in corpus (8)

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• JWST NIRSpec observations of Supernova 1987A -- from the inner ejecta to the reverse shock
• An Imaging Spectroscopic Survey of the Planetary Nebula NGC 7009 with MUSE
• Hitting the slopes: A spectroscopic view of UV continuum slopes of galaxies reveals a reddening at z > 9.5
• Euclid preparation. XXVII. A UV-NIR spectral atlas of compact planetary nebulae for wavelength calibration
• YY Hya and its interstellar environment
• Testing atomic collision theory with the two-photon continuum of astrophysical nebulae
• Cloudy with a chance of starshine: Possible photometric signatures of nebular-dominated emission in $1.5<z<8.5$ JADES galaxies