Template Library

SNID SAGE includes a curated library of 698 supernova and transient spectra for classification.

Built-in Templates

Templates are auto-downloaded on first use (~50 MB). No manual setup required.

Type Count Subtypes
Ia 268 norm, 91T, 91bg, Ia-csm, Ia-pec
II 108 IIP, IIL, IIn, IIb
Ic 68 Ic, Ic-BL
Ib 54 Ib, Ib-pec, Ib-Ca-rich
SLSN 53 SLSN-I, SLSN-II
Galaxy 27 Various galaxy types
TDE 16 Tidal disruption events
AGN 12 AGN-type1, QSO
GAP 10 Gap transients, LRN
Ibn 10 Type Ibn
CV 9 Cataclysmic variables
Star 3 Stellar spectra
LFBOT 3 Fast blue optical transients
Icn 1 Type Icn
KN 1 Kilonova

Storage Format

Templates are stored in HDF5 files grouped by type:

templates/
├── template_index.json      # Metadata index
├── templates_Ia.hdf5        # Type Ia templates
├── templates_II.hdf5        # Type II templates
├── templates_Ib.hdf5        # ... and so on
└── ...

Index Structure

template_index.json contains metadata for all templates:

Version note: "version" is the index/HDF5 format version (schema). The template bank version (downloaded contents) is tracked separately by the templates downloader.

{
  "version": "2.0",
  "template_count": 698,
  "grid_params": {
    "NW": 1024,
    "W0": 2500.0,
    "W1": 10000.0
  },
  "templates": {
    "sn1994D": {
      "type": "Ia",
      "subtype": "norm",
      "redshift": 0.0,
      "epochs": 17,
      "storage_file": "templates_Ia.hdf5"
    }
  }
}

HDF5 Structure

Each HDF5 file contains pre-rebinned spectra and FFTs:

Version note: metadata/version is the HDF5 format version (schema), not the template bank contents version.

templates_Ia.hdf5
├── metadata/
│   ├── version: "2.0"
│   ├── grid_rebinned: true
│   └── wavelength: [2500...10000]  # 1024 points
└── templates/
    └── sn1994D/
        ├── flux: [...]           # Rebinned spectrum
        ├── fft_real: [...]       # Pre-computed FFT
        ├── fft_imag: [...]
        ├── type: "Ia"
        ├── subtype: "norm"
        ├── age: 0.0
        ├── epochs: 17
        └── epoch_data/           # Multi-epoch data
            ├── epoch_-10/
            ├── epoch_0/
            └── ...

Template Manager GUI

Open the standalone Template Manager with snid-sage-templates.

Template Manager showing multi-epoch template sn2008bo with 12 epochs displayed as stacked spectra

The Template Manager lets you: - Browse all templates with search and type filters - Preview spectra with metadata - View multi-epoch template evolution - Create new templates from your spectra

Template creation form with fields for name, type, subtype, redshift, and age

Creating Templates

  1. Open snid-sage-templates → Create Template tab
  2. Load your spectrum file
  3. Fill in metadata (name, type, subtype, age, redshift)
  4. Preview and save

User Templates

Custom templates are stored separately from the built-in bank.

Location

  • User folder: Set on first use and changed later from snid-sage-templates via Change User Folder
  • User index: template_index.user.json
  • User HDF5: templates_Ia.user.hdf5, etc.

Override Behavior

When a user HDF5 exists for a type (e.g., templates_Ia.user.hdf5), it replaces the built-in templates for that type. This prevents duplicates and ensures your edits take effect.

ONIR Templates

For near-infrared analysis, use --profile onir. ONIR templates cover 2000–25000 Å and are stored in separate files (templates_Ia_onir.hdf5, etc.).

Template Helpers

# Open the standalone Template Manager GUI
snid-sage-templates

# Download or refresh the managed built-in template bank
snid-sage-download-templates

# Force a re-download of the managed bank
snid-sage-download-templates --force

See Also