The Type Ia supernova 2004S, a clone of SN 2001el, and the optimal photometric bands for extinction estimation

Kevin Krisciunas*, Peter M. Garnavich, Vallery Stanishev, Nicholas B. Suntzeff, Jose Luis Prieto, Juan Espinoza, David Gonzalez, Maria Elena Salvo, Nancy Elias De La Rosa, Stephen J. Smartt, Justyn R. Maund, Rolf Peter Kudritzki

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    87 Citations (Scopus)


    We present optical (UBVRI) and near-IR (YJHK) photometry of the normal Type la supernova (SN) 2004S. We also present eight optical spectra and one near-IR spectrum of SN 2004S. The light curves and spectra are nearly identical to those of SN 2001el. This is the first time we have seen optical and IR light curves of two Type la SNe match so closely. Within the one parameter family of light curves for normal Type la SNe, that two objects should have such similar light curves implies that they had identical intrinsic colors and produced similar amounts of 56Ni. From the similarities of the light-curve shapes we obtain a set of extinctions as a function of wavelength that allows a simultaneous solution for the distance modulus difference of the two objects, the difference of the host galaxy extinctions, and RV. Since SN 2001el had roughly an order of magnitude more host galaxy extinction than SN 2004S, the value of RV = 2.15-0.22+0.24 pertains primarily to dust in the host galaxy of SN 2001el. We have also shown via Monte Carlo simulations that adding rest-frame J-band photometry to the complement of BVRI photometry of Type la SNe decreases the uncertainty in the distance modulus by a factor of 2.7. A combination of rest-frame optical and near-IR photometry clearly gives more accurate distances than using rest-frame optical photometry alone.

    Original languageEnglish
    Pages (from-to)58-72
    Number of pages15
    JournalAstronomical Journal
    Issue number1
    Publication statusPublished - Jan 2007


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