BLiSS — Blind Line Search System

BLiSS (Blind Line Search System) is an open-source Python package for the automatic detection and identification of emission lines in astronomical spectra.

Rather than requiring users to manually inspect spectra or provide a list of candidate line energies, BLiSS performs a genuine blind line search directly on the data, ranking statistically significant emission-line candidates and optionally identifying them using atomic databases.

Originally developed for X-ray spectroscopy, BLiSS is designed around a general workflow that can be applied to any spectral dataset with associated uncertainties.

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Features

• Blind emission-line search

  • Automatically searches spectra for statistically significant emission features.
  • No prior knowledge of line positions is required.

• Automatic Gaussian fitting

  • Fits candidate features with Gaussian profiles.
  • Provides statistical ranking of all detected lines.

• Continuum-independent workflow

  • Line searches can be performed without defining a global continuum model beforehand.

• Atomic line identification

  • Cross-matches detected features with XSTAR atomic transitions.
  • Supports Doppler velocity constraints.

• Flexible rebinning

  • Rebin spectra by instrumental resolution or target signal-to-noise ratio.

• ISIS integration

  • Automatically generates Gaussian components for ISIS spectral fitting.

• Reproducible analyses

  • Applies identical search criteria across large spectral samples.

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Installation

Install BLiSS directly from PyPI:

pip install bliss-lib

or install the development version from GitHub:

git clone https://github.com/xragua/bliss.git
cd bliss
pip install -e .

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Quick start

import bliss

# Import your spectrum

# Run the blind line search

# Inspect the detected candidates

Example notebooks are available in the notebooks/ directory:

https://github.com/xragua/BLiSS/tree/main/notebooks

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Documentation

GitHub repository:

https://github.com/xragua/bliss

Latest releases:

https://github.com/xragua/bliss/releases

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Requirements

• Python 3.10 or newer
• NumPy
• SciPy
• Pandas
• Astropy
• Matplotlib

These dependencies are installed automatically with BLiSS.

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Citation

If you use BLiSS in your research, please cite:

Abalo, L., Sanjurjo-Ferrín, G., et al. (2026), BLiSS: Blind Line Search System, Astronomy & Computing.

(The citation will be updated once the paper is published.)

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Support

Bug reports, feature requests and suggestions are welcome through GitHub Issues:

https://github.com/xragua/bliss/issues

For scientific questions, you can also contact:

luisabalo.com

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License

This project is distributed under the MIT License.