Peter Nugent's Spectral Templates
Last Revised: March 1, 2007
Ok, I am still working on this page.... templates are here, in various states of disarray. Basic format for the templates are: time (days), lambda(Angstroms), f_lambda(in arbitrary units).You can do this yourself, though it is a major pain. I have gotten good at it over the past few years. Basically it is an art. Careful attention needs to be paid to both the spectroscopic reduction, getting the UV right, looking at some spectrum synthesis models when there are no observations at the epoch/wavelength you want, and knowing where you can get away with interpolation/extrapolation. Most all of the data I used to make these templates is available at SUSPECT, a database I only wish I had when David Branch, Adam Fisher and I started looking at correlations between SN Ia spectra in the very early 1990's. I strongly encourage everyone involved in this game to use it, cite it, and dump your spectra there once they become public.
time is set to 0.0 at the explosion, and f_lambda is now scaled so that it is 0.0 at peak V-band magnitude. I have also included a lightcurve file for each template. Sometimes they are just in B or V, sometimes UBVRIJHK. For the IIn's they include the effective temperature. Instead of being set by the explosion date, they are usually set so they peak in B or V at day 0.0.
Warning to the user: Please use these carefully for doing anything like K-corrections for rates, cosmology, whatever. Understand what you are doing. Read my K-corrections and Extinction Corrections for Type Ia Supernovae paper to get an understanding of what is involved. It is easy to get messed up and I have to go back to the paper frequently to remind myself how to do things right. At the very minimum you will need some piece of code to warp the templates to get the color to be what you want at any given epoch and another piece of code to interpolate between epochs. I have left things usually in some unextinguished form (though SNe like Ib/c rarely have no extinction) so be forewarned. Also remember to check the revision history.
Please let me know if you find any problems.
- Type Ia Branch-normal: This is based on my original work in Nugent, Kim and Perlmutter, PASP (2002), vol. 114, pg. 803. I have modified what appeared there in a few ways. The UV wasn't completely smooth as a function of time. Therefore at the suggestion (forcible) from my friends with the SuperNova Legacy Survey I smoothed them out. In addition, there was a glitch near the R-band in my original template due to one odd-ball supernova being in there. This has been taken care of in the current version. Note, this is a stretch = 1.0 SN Ia template. It is good for that. I think these are good for restframe UBV if you want to stretch the template (between 0.8 < s < 1.1), beyond that I think they can be subject to some systematics.
- Type Ia 1991T-like: This is a brand-new one I've made, based almost exclusively on SN 1991T. It first appeared in Stern et al. (2004) ApJ, vol 612, pg. 690, 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.
- Type Ia 1991bg-like: This is a brand-new one I've made, based on SN 1991bg and SN 1999by. Reference my original paper for the normals and this website. A new paper on this one will be coming out soon.
- Type Ib/c: This is one is based on the work seen in Levan et al. (2005), ApJ (accepted), GRB 020410: A Gamma-Ray Burst Afterglow Discovered by its Supernova Light. It is based on all the Ib/c's Brian Barris put together for me a while back during a summer-time project for SNAP. The lightcurve comes from SN 1999ex based on the work of Hamuy et al. (2002), AJ, vol. 124, pg. 417. You will note that 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 from considerable extinction. Here I basically assume an E(B-V) of 0.4 and corrected accordingly. Because of this, the time of maximum light for this unextinguished template does not show a 0.0 mag in B or V.
- Type Ib/c high-velocity - Hypernovae: These are the high-velocity Ib/c's like SN 1998bw fouond associated with GRB's. This first appeared in the paper cited above for more normal looking Ib/c's.
- Type IIP:
- Type IIL
- Type IIn: The IIn's are just blackbodies. They are based on SN 1999el found in Di Carlo et al. (2002), ApJ, vol. 573, pg, 144.
Here's where I get a little lazy...This is the point I am looking for a new graduate student. Original reference for all of the following Type II's is Gilliland, Phillips and Nugent (1999), ApJ, vol 521, pg. 30. 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 (which is more-or-less a IIP with some continuum thrown in) and a II'n, (which is more-or-less a blackbody with some added emission lines) and redo the latter two. The IIP is fairly good though and is based a lot on the models seen in Baron et al. (2004), ApJ, vol. 616, pg. 91, Type IIP Supernovae as Cosmological Probes: A Spectral-fitting Expanding Atmosphere Model Distance to SN 1999em. The lightcurves are based on the paper by Cappellaro et al. (1997) A&A vol 322, pg. 431