Supernova Spectral Templates
Time-evolving, fluxed spectral series and matching lightcurves for the major supernova types. Last revised July 3, 2024.
The format for the templates is time (days), lambda (Ångstroms), fλ (arbitrary units). time is set to 0.0 at the explosion, and fλ is scaled so that it is 0.0 at peak V-band magnitude. Each template has a lightcurve file — sometimes just B or V, sometimes UBVRIJHK. For the IIn's the lightcurve file includes the effective temperature. Those lightcurves are usually set to peak in B or V at day 0.0 rather than being keyed to the explosion date.
Warning to the user. Please use these carefully for anything like K-corrections for rates, cosmology, whatever — understand what you are doing. Read K-corrections and Extinction Corrections for Type Ia Supernovae first to get a sense of what is involved. It is easy to get messed up; I go back to the paper frequently to remind myself how to do things right.
At a minimum you will need code to warp the templates so the color is what you want at a given epoch, and code to interpolate between epochs. Things are usually left in some unextinguished form (though SNe Ib/c rarely have no extinction), so be forewarned. Also check the revision history.
You can build templates like these yourself, though it is a major pain — basically it is an art. Careful attention has to be paid to the spectroscopic reduction, to getting the UV right, to looking at spectrum synthesis models when there are no observations at the epoch/wavelength you want, and to knowing where you can get away with interpolation/extrapolation. Please let me know if you find any problems.
Type Ia
Branch-normal
Based on my original work in Nugent, Kim & Perlmutter, PASP 114, 803 (2002), modified in a few ways since. The UV wasn't completely smooth as a function of time, so at the (forcible) suggestion of my friends on the SuperNova Legacy Survey I smoothed it out. A glitch near the R-band in the original, caused by one odd-ball supernova, has also been taken care of.
Note this is a stretch = 1.0 SN Ia template, and it is good for that. I think it is good for restframe UBV if you stretch it (0.8 < s < 1.1); beyond that it can be subject to systematics.
1991T-like
Based almost exclusively on SN 1991T. It first appeared in Stern et al., ApJ 612, 690 (2004), Discovery of a Transient U-Band Dropout in a Lyman Break Survey: A Tidally Disrupted Star at z=3.3? I assumed an E(B−V) of 0.2 and corrected accordingly.
1991bg-like
Based on SN 1991bg and SN 1999by. Reference my original paper for the normals, plus this website.
Super-Chandrasekhar
From the study Margot and I did on super-Chandra models — mostly SNe 2012dn and 2009dc, but influenced by the lightcurve of the best-fit model. It was used for all of our bolometric corrections. Reference Fitz Axen & Nugent, ApJ 953, 13 (2023).
Type Ib/c
Type Ib/c
Based on the work in Levan et al., ApJ (2005), GRB 020410: A Gamma-Ray Burst Afterglow Discovered by its Supernova Light, built from all the Ib/c's Brian Barris put together for me during a summer project for SNAP. The lightcurve comes from SN 1999ex, following Hamuy et al., AJ 124, 417 (2002).
This template is blue compared to what you normally see for Ib/c's — my guess is that most, if not all, of these objects suffer considerable extinction. I assume an E(B−V) of 0.4 and correct accordingly, so the time of maximum light for this unextinguished template does not show 0.0 mag in B or V.
High-velocity Ib/c — hypernovae
The high-velocity Ib/c's like SN 1998bw found associated with gamma-ray bursts. First appeared in the paper cited just above.
Type II
Here's where I get a little lazy — this is the point where I am looking for a new graduate student. The original reference for all of the Type II's is Gilliland, Phillips & Nugent, ApJ 521, 30 (1999), High-Redshift Supernovae in the Hubble Deep Field. The IIP's and IIL's now have individual spectral templates. What I still have to do is find a good IIL (more or less a IIP with some continuum thrown in) and a IIn (more or less a blackbody with some added emission lines), and redo the latter two.
The IIP is fairly good, and leans heavily on the models in Baron et al., ApJ 616, 91 (2004), Type IIP Supernovae as Cosmological Probes. The lightcurves are based on Cappellaro et al., A&A 322, 431 (1997).
Type IIn
The IIn's are just blackbodies, based on SN 1999el as found in Di Carlo et al., ApJ 573, 144 (2002).
All Files
| Type | Spectral series | Photometry | Bands |
|---|---|---|---|
| Ia Branch-normal | sn1a_flux.v1.2 | sn1a_lc.v1.2 | UBVRIJHK |
| Ia 1991T-like | sn91t_flux.v1.1 | sn91t_lc.v1.1 | UBVRI |
| Ia 1991bg-like | sn91bg_flux.v1.1 | sn91bg_lc.v1.1 | UBVRI |
| Ia Super-Chandra | superc_flux.v1.0 | superc_lc.v1.0 | V |
| Ib/c | sn1bc_flux.v1.1 | sn1bc_lc.v1.1 | UBVRI |
| Ib/c hypernova | hyper_flux.v1.2 | hyper_lc.v1.2 | V |
| IIP | sn2p_flux.v1.2 | sn2p_lc.v1.2 | V |
| IIL | sn2l_flux.v1.2 | sn2l_lc.v1.2 | V |
| IIn | sn2n_flux.v2.1 | sn2n_lc.v2.1 | V |