present and analyze optical spectroscopic data as well as two spectral models for [SN 2001ig]{} at late times. In §\[s:obs\] we describe our observations and data reduction, and in §\[s:analysis\] we discuss our analysis of the spectra. Our model spectra and their implications are presented in §\[s:model\]. We summarize our conclusions in §\[s:conclusions\].

Observations and Data Reduction {#s:obs}
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Beginning one week after explosion, optical spectra were obtained using the LDSS-2 spectrograph [@Mulchaey01] mounted on the Magellan Baade 6.5-m telescope, the red arm of the dual imager/spectrograph EMMI [@Dekker86] mounted on the European Southern Observatory (ESO) 3.6-m New Technology Telescope, the Low-Resolution Imaging Spectrometer [LRIS; @Oke95] mounted on the Keck I 10-m telescope, and the dual imager/spectrograph EFOSC2 [@Buzzoni84] mounted on the ESO 3.6-m telescope. Our last spectral observation occurred on 2002 Nov. 8, approximately 340 days after explosion. All observations used a $0.7''$–$1.0''$ wide slit and were aligned along the parallactic angle to reduce differential light losses [@Filippenko82]. Table \[t:obs\] summarizes the spectral data of [SN 2001ig]{} presented in this paper.

[lrllrcr]{} 2001 Dec. 11 & 8 & LDSS2 & 3800–9000 & 13 & 1.07 & $2\times90$\
2001 Dec. 13 & 10 & LDSS2 & 5000–10000 & 13 & 