Note: SNCosmo uses Semantic Versioning for its version numbers. Specifically, this means that code written for sncosmo v1.0 will continue to work with any v1.x version. However, exact results may differ between versions in the 1.x series. (For example, due to changes in integration method.)

Major Changes & Additions:

• Add support for Numpy 2.0 (#398)
• Add non-radially varability to bandpasses (#400)
• Adds hdf5 dependancy (#400)

Minor Changes:

• Improve testing (#402)

• Add SkyMapper filters

• Add Nugent Type Ia Super-Chandra model from Fitz Axen and Nugent, (2023) ApJ, v. 953, p. 13

• Drop support for Python 3.8
• New add_effect for G10 and C11 SNIa intrinsic scatter models (#378)
• Salt2 ColorLaw function correction (#389)

• Fix issue with Python 3.12. Added dependency, looseversion, to replace removed distutil module (#387).

• Add ultrasat_ bandpasses (#381).

.._ultrasat: https://www.weizmann.ac.il/ultrasat/

• Add GOTO (#374) and DES u (#371) filters.

Major Changes:

• Dropped support for Python <3.7 (#361)
• Add phase dependence option to PropagationEffect (#359)

Additions & Improvements:

• Add retrained SALT2 models from the DES and Pantheon+ teams (#355)
• Add TESS filter (#357)

• Add P22 SALT3-NIR model (#350)
• Updated SALT3 input calibration (#339)
• Add Gaia filters (#351)
• Improvements to code management

• Add 2MASS filters (#338)
• Add ATLAS filters (#336)

• New zeropoint alias for improved SNANA compatibility (#318)
• Add Roman filters (#218, #322)
• Add the ability to a use SNANA co-add simlibs (#247)
• Fix file paths for Windows users (#324)
• Fix the builtins with poor spline options (#203, #328, #329)
• Various improvements to code and repo management

This release mostly involves modernizing the SNCosmo build system.

• Add Pan-STARRS1 bandpasses (#212)
• Added support for wheels which should now be automatically uploaded to PyPI for any new release (#304).
• Fixed the Zenodo integration. New SNCosmo releases should now automatically be archived to Zenodo.
• Moved citations to the new CITATION.cff format. GitHub and Zenodo will now provide BibTeX entries that can be used to cite SNCosmo (#302).
• Update to the emcee version 3 API. Now only compatible with emcee>=3.
• Migrate from Travis CI to GitHub Actions for continuous integration/tests (#293).
• Bugfixes:
  • Fixed the implementation of the SALT3 error model (#300).
  • Fixed numpy type deprecations.
  • Fixed the documentation for models (#299).

• Add SALT3 model from Kenworthy et al. (2021)
• Various documentation fixes

• Add SUGAR model from Leget et al. (2020)
• Add support for the iminuit 2.0 API (#291).
• Update tox to work with any version of Python 3.
• Bugfixes:
  • Fix flatten_result bug due to API change (#285).

• Add Swift UVOT bandpasses.
• Bugfixes:
  • Fix segfaults in bicubic interpolation.

• Add core-collapse models from Vincenzi et al. (2019)
• New Spectrum class to handle processing and fitting spectral observations.
• Removed appveyor builds.
• Bugfixes:
  • Prevent segfaults in light curve fitting when the minuit fit fails.

• Add ZTF transmission functions
• Bugfixes
  • Corrected pyproject.toml; should help cases where the wrong numpy version was being installed.
  • Remove all references to the six package
  • Fix accidental mutation of bounds inputs in fit_lc and mcmc_lc.

This version is the same as v1.8, with the exception that Python 2 support has been removed, and deprecated functions and attributes have been removed. These were deprecated in v1.5.0 (released April 2017) or before.

On Python 2, pip should automatically install sncosmo v1.8 still. If not, specify sncosmo<2.0.0.

Minor changes:

• The salt2-h17 source model has been renamed to salt2-extended-h17 to make clearer its relation to salt2-extended. It is still available under the old name for backwards compatibility.

• Fix bug in download location of snana-* models latest versions, introduced in v1.8.0.

• Fix bug in download location of salt2-extended model latest version, introduced in v1.8.0.

• Add version 2.0 of many snana-... built-in core-collapse models, based on Pierel et al. 2018 (pull request 229).
• Bugfixes:
  • Fix compatibility with scipy 1.3+ by removing outdated import statements (pull request 238).
  • Fix issue affecting optimization of models with free propagation effects (pull request 236).

• Add SNEMO2, SNEMO7, SNEMO15 source models from Saunders et al. (2018) to built-ins.

• Add Hounsell et al. (2017) SALT2 model to built-ins.
• Add remote_timeout configuration option.
• Build system: remove build-time dependency on astropy helpers.
• Bugfixes:
  • Correctly delete empty files created when a download fails.
  • Use pseudo-inverse when inverting covariance matrix for increased stability.
  • Fix an issue with pickling on Cython 0.26+.
  • Fixed problem where data['fluxcov'] was unintentionally being modified in-place when passed to fit_lc.
  • Fixed problem where 'fluxcov' not recognized as a valid name for covariance column in data in fit_lc.

This is a major new release. The highlight is really close compatibility of the SALT2 model and fitting procedure with snfit, the "official" SALT2 fitter.

• SALT2Source: Internal interpolation scheme of SALT2Source updated to match snfit implementation exactly. Test suite now tests against snfit implementation.

• fit_lc():

  • Handling of model covariance updated to match that of snfit: model covariance is fixed for each fit and fit is repeated until convergence.
  • New arguments phase_range and wave_range. If given, data outside this range will be discarded after an initial fit and additional fits will be performed until convergence. With phase_range=(-15., 45.) and wave_range=(3000., 7000.), behavior approximates that of snfit with default arguments.
  • Added support for covariance in photometric data measurements, and this covariance is used in fit_lc() if present. Covariance is stored as a 'fluxcov' column in the table of measurements.
  • Result includes two new attributes: data_mask, a boolean array indicating which rows in the input data were used in the final fit (since multiple fits might be performed), and nfit, the number of fits performed.
  • New argument warn can be set to False to turn off warnings about dropping bands outside model wavelength range.

• read_lc():

  • Added support for reading snfit-format "covmat" files into a table of photometry:

    >>> data = read_lc('filename', format='salt2', read_covmat=True)
    >>> data['Fluxcov'].shape == (len(data), len(data))
    True
    

  • New keyword argument expand_bands. When True, the returned band column will contain Bandpass objects instead of strings. (Strings converted to bandpass objects using sncosmo.get_bandpass().) This is particularly useful for position-dependent bandpasses in the salt2 file format, such as megacampsf: read_lc() reads the position from the header and feeds the position to get_bandpass() to get a Bandpass object for the correct position.

• Built-in bandpasses and magnitude systems: Many new built-in bandpasses and magnitude systems.

• Configuration: The environment variable SNCOSMO_DATA_DIR can be used to set the path to the data directory. If set, it takes precedence over the data_dir variable in the configuration file ($HOME/.astropy/config/sncosmo.cfg).

• SFD98Map and get_ebv_from_map deprecated in favor of separate package sfdmap which has vastly improved performance (200x faster) for the typical case of scalar coordinates in ICRS frame.
• animate_source() deprecated. This is a "fun extra" that is difficult to test and no longer seems to work.
• Cython implementation of extinction functions has been factored out into a separate Python module called extinction, which is now a dependency.
• Model.bandflux() and Source.bandflux() now integrate on a fixed wavelength grid of 5 angstroms regardless of the wavelength grid of the bandpass. This will result in small differences in results from previous sncosmo versions.
• The internal (publicly undocumented) Spectrum class now acts more like Model; in particular, its bandflux() method now behaves the same way. As Spectrum backs SpectralMagSystem, this makes the integration of models and zeropoint spectra more consistent.
• Experimental (non-public) support for aliases for bandpasses, such as 'SDSS::g' for 'sdssg'.
• Sources now use cubic rather than quadratic spline interpolation internally.
• Model.source_peakmag() and Model.set_source_peakmag() added as convenience functions for Model.source.peakmag() and Model.source.set_peakmag() respectively.
• [Bugfix] Fixed missing import of math module in mcmc_lc() when using the priors keyword. [Backported to v1.3.1] [#143]

This is mostly a bugfix release, but it also drops support for Python 2.6. Python 2.7 is now the minimum supported Python version.

• Updates for compatibility with AstroPy 1.2.

• The registry now handles subclasses more robustly. For example, if magsys is an instance of SpectralMagSystem, the following used to fail:

  sncosmo.register(magsys, 'name')
  sncosmo.get_magsystem('name')
  

  Now this works. [#132]

• [Bugfix] SALT2Source had a bug under Python 3 (only) yielding drastically wrong fluxes. Python 2 was not affected. [#138]

• [API change] Registry functions moved to the top-level namespace, as follows:

  • sncosmo.registry.register() -> sncosmo.register()
  • sncosmo.registry.register_loader() -> sncosmo.register_loader()
  • sncosmo.registry.retrieve() -> deprecated, use class-specific functions such as sncosmo.get_bandpass().

  The old import paths will still work for backwards compatibility.

• nest_lc() now uses the nestle module under the hood. A new keyword method is available which selects different sampling methods implemented by nestle. The new methods provide potential efficiency gains.

• The MLCS2k2 model is now available as a built-in Source, with the name 'mlcs2k2'.

• Bandpasses from the Carnegie Supernova Project added to built-ins.

• In realize_lcs(), a new scatter keyword makes adding noise optional.

• [Bugfix] Fix built-in Bessell bandpass definitions, which were wrong by a term proportional to inverse wavelength. This was due to misinterpretation of the trasmission units. [backported to v1.1.1] [#111]

This is a mostly bugfix release with more solid support for Python 3.

• Added Model.color() method.
• Remove loglmax from result of nest_lc(), which was not officially documented or supported. Use np.max(res.logl) instead.
• Fixed bug that caused non-reproducible behavior in nest_lc() even when numpy.random.seed() was called directly beforehand. [#102]
• Fixed file I/O problems on Python 3 related to string encoding. [#83, #85]
• Fixed problem with SDSS bandpasses being stored as integers internally, preventing them from being used with models with dust. [#100, #101]
• Fixed problem where built-in source name and version strings were being dropped. [#82]
• Minor doc fixes.

• [API change] The API of mcmc_lc has changed significantly

  (the function was marked experimental in previous release).

• [Deprecation] In result of fit_lc, res.cov_names changed to res.vparam_names.
• [Deprecation] In result of nest_lc, res.param_names changed to res.vparam_names. This is for compatibility between the results of fit_lc and nest_lc. [#30]
• [Deprecation] Deprecate flatten keyword argument in fit_lc() in favor of explicit use of flatten_result() function.
• Many new built-in models.
• Many new built-in bandpasses.
• New remote data fetching system.
• SALT2 model covariance available via Model.bandfluxcov() method and modelcov=True keyword argument passed to fit_lc.
• New simulation function, zdist, generates a distribution of redshifts given a volumetric rate function and cosmology.
• New simulation function, realize_lcs, simulates light curve data given a model, parameters, and observations.
• Add color-related keyword arguments to plot_lc().
• Add tighten_ylim keyword argument to plot_lc().
• Add chisq() function and use internally in fit_lc().
• Add SFD98Map class for dealing with SFD (1998) dust maps persistently so that the underlying FITS files are opened only once.
• Update get_ebv_from_map() to work with new SkyCoord class in astropy.coordinates available in astropy v0.3 onward. Previously, this function did not work with astropy v0.4.x (where older coordinates classes had been removed).
• Update to new configuration system available in astropy v0.4 onward. This makes this release incompatible with astropy versions less than 0.4.
• Now compatible with Python 3.
• Increased test coverage.
• Numerous minor bugfixes.

This is non-backwards-compatible release, due to changes in the way models are defined. These changes were made after feedback on the initial design.

The most major change is a new central class Model used throughout the pacakge. A Model instance encompasses a Source and zero or more PropagationEffect instances. This is so that different source models (e.g., SALT2 or spectral time series models) can be combined with arbitrary dust models. The best way to think about this is Source and PropagationEffect define the rest-frame behavior of a SN and dust, and a Model puts these together to determine the observer-frame behavior.

• New classes:
  • sncosmo.Model: new main container class
  • sncosmo.Source: replaces existing Model
  • sncosmo.TimeSeriesSource: replaces existing TimeSeriesModel
  • sncosmo.StretchSource: replaces existing StretchModel
  • sncosmo.SALT2Source: replaces existing SALT2Model
  • sncosmo.PropagationEffect
  • sncosmo.CCM89Dust
  • sncosmo.OD94Dust
  • sncosmo.F99Dust
• New public functions:
  • sncosmo.read_griddata_ascii: Read file with phase wave flux rows
  • sncosmo.read_griddata_fits
  • sncosmo.write_griddata_fits
  • sncosmo.nest_lc: Nested sampling parameter estimation of SN model
  • sncosmo.simulate_vol (EXPERIMENTAL): simulation convenience function.
• Built-ins:
  • updated SALT2 model URLs
  • added SALT2 version 2.4 (Betoule et al 2014)
• Improvements to sncosmo.plot_lc: flexibility and layout
• Many bugfixes

This is a release with mostly bugfixes but a few new features, designed to be backwards compatible with v0.2.0 ahead of API changes coming in the next version.

• New Functions:

  • sncosmo.get_ebv_from_map: E(B-V) at given coordinates from SFD map.
  • sncosmo.read_snana_ascii: Read SNANA ascii format files.
  • sncosmo.read_snana_fits: Read SNANA FITS format files.
  • sncosmo.read_snana_simlib: Read SNANA ascii "SIMLIB" files.

• registry is now case-independent. All of the following now work:

  sncosmo.get_magsystem('AB')
  sncosmo.get_magsystem('Ab')
  sncsomo.get_magsystem('ab')
  

• Photometric data can be unordered in time. Internally, the data are sorted before being used in fitting and typing.

• Numerous bugfixes.

• Added SN 2011fe Nearby Supernova Factory data to built-in models as '2011fe'

• Previously "experimental" functions now included:

  • sncosmo.fit_lc (previously sncosmo.fit_model)
  • sncosmo.read_lc (previously sncosmo.readlc)
  • sncosmo.write_lc (previously sncosmo.writelc)
  • sncosmo.plot_lc (previously sncosmo.plotlc)

• New functions:

  • sncosmo.load_example_data: Example photometric data.
  • sncosmo.mcmc_lc: Markov Chain Monte Carlo parameter estimation.
  • sncosmo.animate_model: Model animation using matplotlib.animation.

• Fitting: sncosmo.fit_lc now uses the iminuit package for minimization by default. This requires the iminuit package to be installed, but the old minimizer (from scipy) can still be used by setting the keyword method='l-bfgs-b'.

• Plotting: Ability to plot model synthetic photometry without observed data, using the syntax:

  >>> sncosmo.plot_lc(model=model, bands=['band1', 'band2'])
  

• Photometric data format: Photometric data format is now more flexible, allowing various names for table columns.

Initial release.