Constraining Photoionization Models With a Reprojected Optical Diagnostic Diagram

Abstract

Optical diagnostic diagrams are powerful tools to separate different ionizing sources in galaxies. However, the model-constraining power of the most widely-used diagrams is very limited and challenging to visualize. In addition, there have always been classification inconsistencies between diagrams based on different line ratios, and ambiguities between regions purely ionized by active galactic nuclei (AGNs) and composite regions. We present a simple reprojection of the 3D line ratio space composed of [N II]$\lambda 6583$/H$\alpha$, [S II]$\lambda \lambda$6716, 6731/H$\alpha$, and [O III]$\lambda$ 5007/H$\beta$, which reveals its model-constraining power and removes the ambiguity for the true composite objects. It highlights the discrepancy between many theoretical models and the data loci. With this reprojection, we can put strong constraints on the photoionization models and the secondary nitrogen abundance prescription. We find that a single nitrogen prescription cannot fit both the star-forming locus and AGN locus simultaneously, with the latter requiring higher N/O ratios. The true composite regions stand separately from both models. We can compute the fractional AGN contributions for the composite regions, and define demarcations with specific upper limits on contamination from AGN or star formation. When the discrepancy about nitrogen prescriptions gets resolved in the future, it would also be possible to make robust metallicity measurements for composite regions and AGNs.

arXiv comment16 pages, 15 figures; accepted for publication in MNRAS

References in corpus (53)

• The Sloan Digital Sky Survey: Technical Summary
• The Seventh Data Release of the Sloan Digital Sky Survey
• Starburst99: Synthesis Models for Galaxies with Active Star Formation
• The Host Galaxies of AGN
• The Origin of the Mass--Metallicity Relation: Insights from 53,000 Star-Forming Galaxies in the SDSS
• Theoretical Modeling of Starburst Galaxies
• The 2.5 m Telescope of the Sloan Digital Sky Survey
• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• The Host Galaxies and Classification of Active Galactic Nuclei
• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies
• Using Strong Lines to Estimate Abundances in Extragalactic HII Regions and Starburst Galaxies
• Nuclear Activity in Nearby Galaxies
• The Multi-Object, Fiber-Fed Spectrographs for SDSS and the Baryon Oscillation Spectroscopic Survey
• The SAURON project - V. Integral-field emission-line kinematics of 48 elliptical and lenticular galaxies
• A comprehensive classification of galaxies in the SDSS: How to tell true from fake AGN?
• The MaNGA Integral Field Unit Fiber Feed System for the Sloan 2.5 m Telescope
• Spectroscopy of Outlying H II Regions in Spiral Galaxies: Abundances and Radial Gradients
• The Data Reduction Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey
• The Composition Gradient in M101 Revisited. II. Electron Temperatures and Implications for the Nebular Abundance Scale
• The X-ray to optical-UV luminosity ratio of X-ray selected Type 1 AGN in XMM-COSMOS
• The SDSS-IV MaNGA Sample: Design, Optimization, and Usage Considerations
• SDSS IV MaNGA - Spatially resolved diagnostic diagrams: A proof that many galaxies are LIERs
• SDSS-IV MaNGA IFS Galaxy Survey --- Survey Design, Execution, and Initial Data Quality
• The Data Analysis Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey: Overview
• The SAURON project XVI: On the Sources of Ionisation for the Gas in Elliptical and Lenticular Galaxies
• On the Origin of [OII] Emission in Red Sequence and Post-starburst Galaxies
• SDSS IV MaNGA - Metallicity and nitrogen abundance gradients in local galaxies
• Dusty, Radiation Pressure Dominated Photoionization. I. Model Description, Structure And Grids
• New Strong Line Abundance Diagnostics for \HII Regions: Effects of $\kappa$-Distributed Electron Energies and New Atomic Data
• Chemical abundances in high-redshift galaxies: A powerful new emission line diagnostic
• SDSS-IV/MaNGA: Spectrophotometric Calibration Technique
• The Nature of LINER-like Emission in Red Galaxies
• Dusty, Radiation Pressure Dominated Photoionization. II. Multi-Wavelength Emission Line Diagnostics for Narrow Line Regions
• The Data Analysis Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey: Emission-Line Modeling
• SDSS-IV MaNGA: Spatially resolved star formation histories in galaxies as a function of galaxy mass and type
• Are the Narrow Line Regions in Active Galaxies Dusty and Radiation Pressure Dominated?
• IZI: Inferring the Gas Phase Metallicity (Z) and Ionization Parameter (q) of Ionized Nebulae using Bayesian Statistics
• Chemical Abundance Calibrations for the Narrow-Line-Region of Active Galaxies
• Abundance scaling in stars, nebulae and galaxies
• An Assessment of the Energy Budgets of Low-Ionization Nuclear Emission Regions
• A New Diagnostic to Separate Line Emission from Star Formation, Shocks, and AGN Simultaneously in IFU Data
• The mass-metallicity relation of local active galaxies
• WARPFIELD-EMP: The Self-Consistent Prediction of Emission Lines from Evolving HII Regions in Dense Molecular Clouds
• Chemical evolution of starburst galaxies: How does star formation proceed?
• SDSS-IV MaNGA: Variations in the N/O -- O/H relation bias metallicity gradient measurements
• Galaxy emission line classification using 3D line ratio diagrams
• Precision Spectrophotometry at the Level of 0.1%
• Comparison of Theoretical Starburst Photoionisation Models for Optical Diagnostics
• Upper boundaries of AGN regions in optical diagnostic diagrams
• Nitrogen-to-Oxygen Abundance Ratio Variation In Quiescent Galaxies

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• SDSS-IV MaNGA: Refining Strong Line Diagnostic Classifications Using Spatially Resolved Gas Dynamics
• A Catalog of 406 AGNs in MaNGA: A Connection between Radio-mode AGN and Star Formation Quenching
• Correlation between the gas-phase metallicity and ionization parameter in extragalactic HII regions
• Chemical abundances of Seyfert 2 AGNs IV. Composite models calculated by photoionization + shocks
• An IFU View of the Active Galactic Nuclei in MaNGA Galaxy Pairs
• The Host Galaxies of Radio AGN: New Views from Combining LoTSS and MaNGA Observations
• Self-Consistent Grain Depletions and Abundances II: Effects on strong-line diagnostics of extragalactic H II regions
• How do supernova remnants cool? -- I. Morphology, optical emission lines, and shocks
• The ALMaQUEST Survey XV: The Dependence of the Molecular-to-Atomic Gas Ratios on Resolved Optical Diagnostics
• The need for multicomponent dust attenuation in modeling nebular emission: Constraints from SDSS-IV MaNGA
• Beyond Traditional Diagnostics: Identifying Active Galactic Nuclei with Spectral Energy Distribution Fitting in DESI Data
• Ionized gas in quiescent galaxies: Temperature measurement and constraint on the ionization source
• Mid-Infrared Variability in Nearby Galaxies from the MaNGA Sample
• Nebular Dust Attenuation with the Balmer and Paschen Lines based on the MaNGA Survey
• A Spatially Resolved Evolutionary Sequence of Multi-wavelength AGN Host Galaxies
• How do supernova remnants cool? II. Machine learning analysis of supernova remnant simulations
• Infrared and Optical Emission-line Diagnostics
• The Eddington Ratio Distribution of Narrow Line Active Galactic Nuclei
• Physical Drivers of Emission Line Diversity of SDSS Seyfert 2s and LINERs After Removal of Contributions by Star Formation
• SDSS-IV MaNGA: Data-Model Discrepancy in Temperature-sensitive Line Ratios for Star-forming Galaxies
• Chemical abundances in Seyfert galaxies -- VII. Direct abundance determination of neon based on optical and infrared emission lines