Contents Menu Expand Light mode Dark mode Auto light/dark, in light mode Auto light/dark, in dark mode Skip to content
tengri
Logo
tengri

Foundations

  • Quickstart
  • Why JAX
  • SED Anatomy
  • Discovering the Menu
  • Building Models

Fitting workflows

  • Fitting Photometry
  • Fitting Spectroscopy
  • Joint Photometry + Spectroscopy

Physics deep dives

  • Emission Lines
  • 09_parameter_sweeps

Reference

  • Performance
  • Memory expectations
  • Units and conventions

Gallery

  • Advanced Topics
    • Age-Dust-Metallicity Degeneracy: Fisher Analysis
    • Gradient Sensitivity Heatmap
    • Hierarchical PSD Inference
    • Joint Photometry + Spectroscopy Fit
    • Component orchestrator end-to-end
    • Panchromatic SED: UV to Radio
  • AGN Models
    • X-ray Corona: Spectral Index vs Bolometric Luminosity 2D Sweep
    • SKIRTOR Torus: Viewing Angle Sweep
    • AGN SEDModel Hierarchy
    • QSOgen Disc Continuum: Bolometric Luminosity
    • SKIRTOR Torus: Opening Angle Sweep
    • Polar Dust: Temperature Sweep in AGN Torus
    • QSOgen Dust Reddening: Intrinsic AGN Obscuration
    • QSOgen Emission Line Scaling: Rest-UV to Optical SED
    • SKIRTOR Torus: Radial Dust Power-Law Sweep
    • SKIRTOR Torus: Optical Depth Sweep
    • AGN SED Templates
    • Type 1 vs Type 2 AGN: Geometric Unification
    • Narrow and Broad Line Region Emission
    • Polar Dust in AGN: IR Bump from Polar Dust Torus
    • QSOgen Empirical Quasar Template
    • RELAGN Spin Sweep
    • SKIRTOR Clumpy Torus: Inclination and Optical Depth
    • Torus Models Comparison: Nenkova vs Silva04
  • Hensley & Draine 2023 Astrodust+PAH
    • Astrodust+PAH size distribution
    • Astrodust+PAH emission vs log U
    • Astrodust+PAH per-component decomposition
    • DustEmissionSEDComponent — swap MBB / PAHspec / Astrodust
    • Astrodust+PAH ionization fraction and alignment
    • Astrodust+PAH extinction, scattering, and albedo
    • Astrodust+PAH spinning-dust microwave emission
    • Astrodust+PAH polarized emission and polarization fraction
  • Dust Models
    • Hensley & Draine 2023 Astrodust+PAH: log U sweep
    • Attenuation Law Comparison
    • BOSA: log L_TIR sweep at fixed log sSFR
    • BOSA: log sSFR sweep at fixed log L_TIR
    • Modified Blackbody Dust Temperature
    • Dust Attenuation Curves
    • Dust Emission Models: Overview
    • Dust Geometry: Screen vs Mixed vs Clumpy
    • Dust IR SED: q_PAH × U_min Grid
    • Attenuation Curve Slope (δ)
    • Draine+2021 PAHspec: log U sweep at fixed (starlight, ion, size)
    • Draine+2021 PAHspec: starlight-spectrum sweep at fixed log U
    • PAH Mass Fraction (q_PAH)
    • Birth Cloud Optical Depth (τ_BC)
    • Diffuse ISM Optical Depth (τ_diff)
    • THEMIS: q_HAC sweep at fixed U_min
    • THEMIS: U_min sweep at fixed q_HAC
    • Two-Component Dust SEDModel
    • Draine & Li Minimum Radiation Field (U_min)
    • UV Bump Strength (dust_bump_strength)
  • IGM
    • Damped Lyman-Alpha (DLA) Absorption
    • IGM Transmission Model Comparison
    • IGM Transmission vs Redshift
    • IGM Absorption Evolution with Redshift
  • Inference Methods
    • Convergence Diagnostics
    • Corner Plot with Truth Overlay
    • Population PSD Recovery: 1/√N Convergence
    • MAP vs geoVI Posterior Comparison
    • Population VI scaling: time, memory, and convergence
    • Prior vs Posterior: Parameter Constraints from Inference
  • Metallicity
    • α/Fe Enhancement (met_alpha_fe)
    • Metallicity Sweep: Panchromatic SED
    • Stellar Metallicity (log Z/Z_⊙)
    • Stellar Continuum: Metallicity × Age Grid
    • Chemical Evolution: Model Comparison
  • Multiwavelength
    • FIR–Radio Correlation
    • Panchromatic AGN Host SED
    • AGN Contribution to Composite SEDs
    • Dust Energy Balance: UV Attenuation ↔ IR Emission
    • Panchromatic Star-Forming Galaxy
    • Panchromatic SED: Redshift Evolution
  • Nebular Emission
    • BPT with Cue: Every Knob, One Panel Each
    • BPT Diagrams with Cue: 2D Grid in (log U, log Z_gas)
    • BPT Diagnostics: Star Formation, Shocks, and AGN
    • Diffuse Ionized Gas Fraction (f_DIG)
    • Ionizing Photon Escape Fraction (f_esc)
    • Emission Line Width (σ in km/s)
    • Ionization Parameter (logU)
    • Gas Metallicity (log Z/Zsun)
    • Nebular Emission: Dependence on Stellar Population Age
    • Nebular Backends: BakedIn vs CloudyGrid vs Cue
    • BPT Diagram: Ionization Parameter Sequence
    • Nebular Gas Density: Metallicity Variation
    • Nebular Emission Backends
    • Nebular Shock Emission (MAPPINGS V)
  • Photometry
    • SDSS Filter Transmission Curves
    • Filter Set Comparison
    • Photometric SED Fit
    • Filter Sampling Across Redshift
    • S/N Ratio Parameter Sweep
  • Quick Start
    • First Photometric Fit
    • SED Components
  • Radio
    • Radio Spectral Index (α_sf)
    • FIR-Radio Correlation (q_IR)
    • FIR-Radio Correlation: L_IR Luminosity Sweep
    • AGN Radio Loudness (R)
  • Star Formation Histories
    • SFH Recovery Across Four Burstiness Regimes
    • Chemical Evolution: Metallicity History Models
    • Delayed-τ SFH: Star Formation Timescale
    • Double Power-Law SFH: 2D Parameter Grid (α × β)
    • Double Power-Law SFH: Rising Slope α
    • Double Power-Law SFH: Falling Slope β
    • Log-Normal SFH: Peak Lookback Time
    • Parametric SFH Models
    • Alternative PSD Models
    • PSD Parameter Space and Burstiness
    • Stochastic SFH: Burstiness Amplitude σ
    • Stochastic SFH: Burstiness Timescale τ
    • SFH with Double Bursts: Old and Recent Star Formation
    • SFH Quenching Scenarios: Constant, Exponential, Sharp, and Burst+Decay
    • Stochastic SFH from GP Correlated Fields
    • The Wrong-SEDModel Trap: Parametric Bias in Derived Quantities
  • Spectroscopy
    • Instrumental Resolution Sweep
    • Key Spectral Features as Age and Metallicity Probes
    • Spectroscopic SED Fit
    • Stellar Velocity Dispersion Sweep
  • Stellar Population Synthesis
    • Stellar Population Aging: SSP at Solar Metallicity
    • SSP Grid Visualization: Age and Metallicity
    • IMF Comparison: Mass-to-Light Ratio
    • Stellar Metallicity Effects on SED
  • X-ray Emission
    • High-Energy Cutoff Variation
    • X-ray Normalisation via UV-to-X-ray Slope
    • AGN X-ray Emission and Corona
    • X-ray Spectral Index Variation
    • X-ray Binary Population from Star Formation
  • Examples gallery
  • Advanced Topics
  • AGN Models
  • Hensley & Draine 2023 Astrodust+PAH
  • Dust Models
  • IGM
  • Inference Methods
  • Metallicity
  • Multiwavelength
  • Nebular Emission
  • Photometry
  • Quick Start
  • Radio
  • Star Formation Histories
  • Spectroscopy
  • Stellar Population Synthesis
  • X-ray Emission
  • Examples gallery
    • Advanced Topics
      • Age-Dust-Metallicity Degeneracy: Fisher Analysis
      • Gradient Sensitivity Heatmap
      • Hierarchical PSD Inference
      • Joint Photometry + Spectroscopy Fit
      • Component orchestrator end-to-end
      • Panchromatic SED: UV to Radio
    • AGN Models
      • X-ray Corona: Spectral Index vs Bolometric Luminosity 2D Sweep
      • SKIRTOR Torus: Viewing Angle Sweep
      • AGN SEDModel Hierarchy
      • QSOgen Disc Continuum: Bolometric Luminosity
      • SKIRTOR Torus: Opening Angle Sweep
      • Polar Dust: Temperature Sweep in AGN Torus
      • QSOgen Dust Reddening: Intrinsic AGN Obscuration
      • QSOgen Emission Line Scaling: Rest-UV to Optical SED
      • SKIRTOR Torus: Radial Dust Power-Law Sweep
      • SKIRTOR Torus: Optical Depth Sweep
      • AGN SED Templates
      • Type 1 vs Type 2 AGN: Geometric Unification
      • Narrow and Broad Line Region Emission
      • Polar Dust in AGN: IR Bump from Polar Dust Torus
      • QSOgen Empirical Quasar Template
      • RELAGN Spin Sweep
      • SKIRTOR Clumpy Torus: Inclination and Optical Depth
      • Torus Models Comparison: Nenkova vs Silva04
    • Hensley & Draine 2023 Astrodust+PAH
      • Astrodust+PAH size distribution
      • Astrodust+PAH emission vs log U
      • Astrodust+PAH per-component decomposition
      • DustEmissionSEDComponent — swap MBB / PAHspec / Astrodust
      • Astrodust+PAH ionization fraction and alignment
      • Astrodust+PAH extinction, scattering, and albedo
      • Astrodust+PAH spinning-dust microwave emission
      • Astrodust+PAH polarized emission and polarization fraction
    • Dust Models
      • Hensley & Draine 2023 Astrodust+PAH: log U sweep
      • Attenuation Law Comparison
      • BOSA: log L_TIR sweep at fixed log sSFR
      • BOSA: log sSFR sweep at fixed log L_TIR
      • Modified Blackbody Dust Temperature
      • Dust Attenuation Curves
      • Dust Emission Models: Overview
      • Dust Geometry: Screen vs Mixed vs Clumpy
      • Dust IR SED: q_PAH × U_min Grid
      • Attenuation Curve Slope (δ)
      • Draine+2021 PAHspec: log U sweep at fixed (starlight, ion, size)
      • Draine+2021 PAHspec: starlight-spectrum sweep at fixed log U
      • PAH Mass Fraction (q_PAH)
      • Birth Cloud Optical Depth (τ_BC)
      • Diffuse ISM Optical Depth (τ_diff)
      • THEMIS: q_HAC sweep at fixed U_min
      • THEMIS: U_min sweep at fixed q_HAC
      • Two-Component Dust SEDModel
      • Draine & Li Minimum Radiation Field (U_min)
      • UV Bump Strength (dust_bump_strength)
    • IGM
      • Damped Lyman-Alpha (DLA) Absorption
      • IGM Transmission Model Comparison
      • IGM Transmission vs Redshift
      • IGM Absorption Evolution with Redshift
    • Inference Methods
      • Convergence Diagnostics
      • Corner Plot with Truth Overlay
      • Population PSD Recovery: 1/√N Convergence
      • MAP vs geoVI Posterior Comparison
      • Population VI scaling: time, memory, and convergence
      • Prior vs Posterior: Parameter Constraints from Inference
    • Metallicity
      • α/Fe Enhancement (met_alpha_fe)
      • Metallicity Sweep: Panchromatic SED
      • Stellar Metallicity (log Z/Z_⊙)
      • Stellar Continuum: Metallicity × Age Grid
      • Chemical Evolution: Model Comparison
    • Multiwavelength
      • FIR–Radio Correlation
      • Panchromatic AGN Host SED
      • AGN Contribution to Composite SEDs
      • Dust Energy Balance: UV Attenuation ↔ IR Emission
      • Panchromatic Star-Forming Galaxy
      • Panchromatic SED: Redshift Evolution
    • Nebular Emission
      • BPT with Cue: Every Knob, One Panel Each
      • BPT Diagrams with Cue: 2D Grid in (log U, log Z_gas)
      • BPT Diagnostics: Star Formation, Shocks, and AGN
      • Diffuse Ionized Gas Fraction (f_DIG)
      • Ionizing Photon Escape Fraction (f_esc)
      • Emission Line Width (σ in km/s)
      • Ionization Parameter (logU)
      • Gas Metallicity (log Z/Zsun)
      • Nebular Emission: Dependence on Stellar Population Age
      • Nebular Backends: BakedIn vs CloudyGrid vs Cue
      • BPT Diagram: Ionization Parameter Sequence
      • Nebular Gas Density: Metallicity Variation
      • Nebular Emission Backends
      • Nebular Shock Emission (MAPPINGS V)
    • Photometry
      • SDSS Filter Transmission Curves
      • Filter Set Comparison
      • Photometric SED Fit
      • Filter Sampling Across Redshift
      • S/N Ratio Parameter Sweep
    • Quick Start
      • First Photometric Fit
      • SED Components
    • Radio
      • Radio Spectral Index (α_sf)
      • FIR-Radio Correlation (q_IR)
      • FIR-Radio Correlation: L_IR Luminosity Sweep
      • AGN Radio Loudness (R)
    • Star Formation Histories
      • SFH Recovery Across Four Burstiness Regimes
      • Chemical Evolution: Metallicity History Models
      • Delayed-τ SFH: Star Formation Timescale
      • Double Power-Law SFH: 2D Parameter Grid (α × β)
      • Double Power-Law SFH: Rising Slope α
      • Double Power-Law SFH: Falling Slope β
      • Log-Normal SFH: Peak Lookback Time
      • Parametric SFH Models
      • Alternative PSD Models
      • PSD Parameter Space and Burstiness
      • Stochastic SFH: Burstiness Amplitude σ
      • Stochastic SFH: Burstiness Timescale τ
      • SFH with Double Bursts: Old and Recent Star Formation
      • SFH Quenching Scenarios: Constant, Exponential, Sharp, and Burst+Decay
      • Stochastic SFH from GP Correlated Fields
      • The Wrong-SEDModel Trap: Parametric Bias in Derived Quantities
    • Spectroscopy
      • Instrumental Resolution Sweep
      • Key Spectral Features as Age and Metallicity Probes
      • Spectroscopic SED Fit
      • Stellar Velocity Dispersion Sweep
    • Stellar Population Synthesis
      • Stellar Population Aging: SSP at Solar Metallicity
      • SSP Grid Visualization: Age and Metallicity
      • IMF Comparison: Mass-to-Light Ratio
      • Stellar Metallicity Effects on SED
    • X-ray Emission
      • High-Energy Cutoff Variation
      • X-ray Normalisation via UV-to-X-ray Slope
      • AGN X-ray Emission and Corona
      • X-ray Spectral Index Variation
      • X-ray Binary Population from Star Formation
    • Examples gallery
    • Advanced Topics
    • AGN Models
    • Hensley & Draine 2023 Astrodust+PAH
    • Dust Models
    • IGM
    • Inference Methods
    • Metallicity
    • Multiwavelength
    • Nebular Emission
    • Photometry
    • Quick Start
    • Radio
    • Star Formation Histories
    • Spectroscopy
    • Stellar Population Synthesis
    • X-ray Emission
Back to top
View this page
Edit this page

Metallicity¶

Stellar metallicity Z and α-element enhancement effects on the SED.

α/Fe Enhancement (met_alpha_fe)

α/Fe Enhancement (met_alpha_fe)

Metallicity Sweep: Panchromatic SED

Metallicity Sweep: Panchromatic SED

Stellar Metallicity (log Z/Z_⊙)

Stellar Metallicity (log Z/Z_⊙)

Stellar Continuum: Metallicity × Age Grid

Stellar Continuum: Metallicity × Age Grid

Chemical Evolution: Model Comparison

Chemical Evolution: Model Comparison
Next
α/Fe Enhancement (met_alpha_fe)
Previous
Prior vs Posterior: Parameter Constraints from Inference
Copyright © 2026, Suchetha Cooray
Made with Sphinx and @pradyunsg's Furo