Carnegie Supernova Project: Observations of Type IIn supernovae
  The observational diversity displayed by various Type IIn supernovae (SNe
IIn) is explored and quantified. In doing so, a more coherent picture ascribing
the variety of observed SNe IIn types to particular progenitor scenarios is
sought. Carnegie Supernova Project (CSP) optical and near-infrared light curves
and visual-wavelength spectroscopy of the Type IIn SNe 2005kj, 2006aa, 2006bo,
2006qq, and 2008fq are presented. Combined with previously published
observations of the Type IIn SNe 2005ip and 2006jd, the full CSP sample is used
to derive physical parameters that describe the nature of the interaction
between the expanding SN ejecta and the circumstellar material (CSM). For each
SN of our sample, we find counterparts, identifying objects similar to SNe
1994W (SN 2006bo), 1998S (SN 2008fq), and 1988Z (SN 2006qq). We present the
unprecedented initial $u$-band plateau of SN 2006aa, and its peculiar late-time
luminosity and temperature evolution. For each SN, mass-loss rates of
10$^{-4}-10^{-2}$ $M_{\odot}$ yr$^{-1}$ are derived, assuming the CSM was
formed by steady winds. Typically wind velocities of a few hundred km s$^{-1}$
are also computed. The CSP SN IIn sample seems to be divided into subcategories
rather than to have exhibited a continuum of observational properties. The wind
and mass-loss parameters would favor a luminous blue variable progenitor
scenario. However the assumptions made to derive those parameters strongly
influence the results, and therefore, other progenitor channels behind SNe IIn
cannot be excluded at this time.
