Configuration Files

Overview

MapLines uses YAML configuration files to define the emission-line model and the parameter constraints used during fitting.

These files allow flexible modeling of complex emission-line systems.

Typical configuration files

Two configuration files are typically used:

  • config.yml

  • line_prop.yml

The first defines the general fitting setup, while the second describes the emission-line components.

Line properties

The line configuration file defines:

  • line names

  • rest wavelengths

  • amplitude relations

  • velocity constraints

  • width constraints

Example structure:

Halpha:
    lambda: 6562.8
    amplitude: free
    velocity: tied
    width: tied

Parameter linking

MapLines allows parameters to be tied between components.

For example:

  • velocity of [NII] tied to Hα

  • width of multiple lines tied together

This ensures physically consistent models.

Priors

Parameter priors define the allowed ranges for each parameter.

These include:

  • amplitude limits

  • velocity limits

  • width limits

The priors are evaluated by the module:

MapLines.tools.priors

which defines the likelihood and posterior functions used by the MCMC sampler.