Comparison of Theoretical Starburst Photoionisation Models for Optical Diagnostics. (arXiv:1905.09528v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+DAgostino_J/0/1/0/all/0/1">Joshua J. D'Agostino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kewley_L/0/1/0/all/0/1">Lisa J. Kewley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Groves_B/0/1/0/all/0/1">Brent Groves</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Byler_N/0/1/0/all/0/1">Nell Byler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sutherland_R/0/1/0/all/0/1">Ralph S. Sutherland</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nicholls_D/0/1/0/all/0/1">David Nicholls</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Leitherer_C/0/1/0/all/0/1">Claus Leitherer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stanway_E/0/1/0/all/0/1">Elizabeth R. Stanway</a>
We study and compare different examples of stellar evolutionary synthesis
input parameters used to produce photoionisation model grids using the MAPPINGS
V modelling code. The aim of this study is to (a) explore the systematic
effects of various stellar evolutionary synthesis model parameters on the
interpretation of emission lines in optical strong-line diagnostic diagrams,
(b) characterise the combination of parameters able to reproduce the spread of
local galaxies located in the star-forming region in the Sloan Digital Sky
Survey, and (c) investigate the emission from extremely metal-poor galaxies
using photoionisation models. We explore and compare the stellar input ionising
spectrum (stellar population synthesis code [Starburst99, SLUG, BPASS], stellar
evolutionary tracks, stellar atmospheres, star-formation history, sampling of
the initial mass function) as well as parameters intrinsic to the H II region
(metallicity, ionisation parameter, pressure, H II region boundedness). We also
perform a comparison of the photoionisation codes MAPPINGS and CLOUDY. On the
variations in the ionising spectrum model parameters, we find that the
differences in strong emission-line ratios between varying models for a given
input model parameter are small, on average ~0.1 dex. An average difference of
~0.1 dex in emission-line ratio is also found between models produced with
MAPPINGS and CLOUDY. Large differences between the emission-line ratios are
found when comparing intrinsic H II region parameters. We find that
low-metallicity galaxies are better explained by a density-bounded H II region
and higher pressures better encompass the spread of galaxies at high redshift.
We study and compare different examples of stellar evolutionary synthesis
input parameters used to produce photoionisation model grids using the MAPPINGS
V modelling code. The aim of this study is to (a) explore the systematic
effects of various stellar evolutionary synthesis model parameters on the
interpretation of emission lines in optical strong-line diagnostic diagrams,
(b) characterise the combination of parameters able to reproduce the spread of
local galaxies located in the star-forming region in the Sloan Digital Sky
Survey, and (c) investigate the emission from extremely metal-poor galaxies
using photoionisation models. We explore and compare the stellar input ionising
spectrum (stellar population synthesis code [Starburst99, SLUG, BPASS], stellar
evolutionary tracks, stellar atmospheres, star-formation history, sampling of
the initial mass function) as well as parameters intrinsic to the H II region
(metallicity, ionisation parameter, pressure, H II region boundedness). We also
perform a comparison of the photoionisation codes MAPPINGS and CLOUDY. On the
variations in the ionising spectrum model parameters, we find that the
differences in strong emission-line ratios between varying models for a given
input model parameter are small, on average ~0.1 dex. An average difference of
~0.1 dex in emission-line ratio is also found between models produced with
MAPPINGS and CLOUDY. Large differences between the emission-line ratios are
found when comparing intrinsic H II region parameters. We find that
low-metallicity galaxies are better explained by a density-bounded H II region
and higher pressures better encompass the spread of galaxies at high redshift.
http://arxiv.org/icons/sfx.gif
