Line List Format#

Load custom spectral line lists for identification and analysis.

Overview#

The Line List format is used for importing custom lists of spectral lines that can be overlaid on spectroscopic data for line identification and analysis. Line lists specify the rest wavelengths of emission or absorption features and their labels.

Warning

The Line Lists functionality is still under active development. For more information see Line Lists in the plugins documentation.

Usage#

import jdaviz as jd
from astropy.table import QTable
from astropy import units as u

# Create a line list table
line_table = QTable({
    'linename': ['H-alpha', 'H-beta', 'O-III'],
    'rest': [6562.8, 4861.3, 5006.8] * u.AA
})

# Load the line list
jd.load(line_table, format='Line List', line_list_label='Balmer Lines')

Data Requirements#

The data must be an astropy.table.QTable with the following structure:

Required Columns#

linename: Names/labels for each spectral line (string column)
rest: Rest wavelengths of the lines, with astropy units attached (Quantity column)

The rest wavelengths must:

Be positive values
Have units (e.g., Angstroms, nanometers, GHz)
Be in the rest frame (observed wavelength accounting will be handled by the tool)

Supported File Formats#

ECSV files with the required columns
Python astropy.table.QTable objects created in memory

When loading from a file, ensure the file can be read by astropy.table.QTable.read and contains the required columns with proper units.

Data Validation#

The Line List importer validates:

Input is a QTable
Required columns (‘linename’ and ‘rest’) are present
Rest column has astropy units
All rest values are positive
Line list name doesn’t conflict with existing loaded lists

Line List Label#

Each imported line list requires a unique label:

jd.load(line_table, format='Line List', line_list_label='My Lines')

If no label is provided, the default label ‘Imported’ will be used. The label cannot duplicate an already-loaded line list name.