REDBACK: a Bayesian inference software package for electromagnetic transients

Nikhil Sarin, Moritz Hübner, Conor M.B. Omand, Christian N. Setzer, Steve Schulze, Naresh Adhikari, Ana Sagués-Carracedo, Shanika Galaudage, Wendy F. Wallace, Gavin P. Lamb, En Tzu Lin

Research output: Contribution to journalArticlepeer-review


Fulfilling the rich promise of rapid advances in time-domain astronomy is only possible through confronting our observations with physical models and extracting the parameters that best describe what we see. Here, we introduce REDBACK; a Bayesian inference software package for electromagnetic transients. REDBACK provides an object-orientated PYTHON interface to over 12 different samplers and over 100 different models for kilonovae, supernovae, gamma-ray burst afterglows, tidal disruption events, engine-driven transients among other explosive transients. The models range in complexity from simple analytical and semi-analytical models to surrogates built upon numerical simulations accelerated via machine learning. REDBACK also provides a simple interface for downloading and processing data from various catalogues such as Swift and FINK. The software can also serve as an engine to simulate transients for telescopes such as the Zwicky Transient Facility and Vera Rubin with realistic cadences, limiting magnitudes, and sky coverage or a hypothetical user-constructed survey or a generic transient for target-of-opportunity observations with different telescopes. As a demonstration of its capabilities, we show how REDBACK can be used to jointly fit the spectrum and photometry of a kilonova, enabling a more powerful, holistic probe into the properties of a transient. We also showcase general examples of how REDBACK can be used as a tool to simulate transients for realistic surveys, fit models to real, simulated, or private data, multimessenger inference with gravitational waves, and serve as an end-to-end software toolkit for parameter estimation and interpreting the nature of electromagnetic transients.

Original languageEnglish
Pages (from-to)1203-1227
Number of pages25
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Early online date13 May 2024
Publication statusE-pub ahead of print - 13 May 2024
Externally publishedYes

Data Availability Statement

The software package along with example scripts for all analysis demonstrated in this manuscript alongside a plotting notebook to generate all the plots as well as other examples are available at The specific result objects for each of the analyses presented here are available at REDBACK is available on PYPI. This paper uses v1.0 release of REDBACK with documentation at The data for all transients is available at the OAC (Guillochon et al. 2017) gathered through the REDBACKget_data module or hosted at


  • black hole–neutron star mergers
  • gamma-ray bursts
  • neutron star mergers
  • software: data analysis
  • transients: supernovae
  • transients: tidal disruption events

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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