Multi-wavelength Observations of the Enduring Type IIn Supernovae 2005ip and 2006jd

TL;DR

This study provides a detailed multi-wavelength observational analysis of two enduring Type IIn supernovae, revealing similarities to the 1988Z-like subclass and highlighting differences in progenitor mass-loss histories over a 6.5-year period.

Contribution

It offers the first extensive multi-wavelength dataset for SNe 2005ip and 2006jd, comparing their properties and progenitor mass-loss histories, including dust components and late-time emission.

Findings

SN 2005ip and 2006jd show 1988Z-like spectral features

SN 2006jd exhibits an unprecedented late-time r-band excess

Progenitor of SN 2006jd likely had a major mass-loss event

Abstract

We present an observational study of the Type IIn supernovae (SNe IIn) 2005ip and 2006jd. Broad-band UV, optical and near-IR photometry, and visual-wavelength spectroscopy of SN 2005ip complement and extend upon published observations to 6.5 years past discovery. Our observations of SN 2006jd extend from UV to mid-infrared wavelengths, and like SN 2005ip, are compared to reported X-ray measurements to understand the nature of the progenitor. Both objects display a number of similarities with the 1988Z-like subclass of SN IIn including: (i) remarkably similar early- and late-phase optical spectra, (ii) a variety of high ionization coronal lines, (iii) long-duration optical and near-IR emission and, (iv) evidence of cold and warm dust components. However, diversity is apparent including an unprecedented late-time r-band excess in SN 2006jd.The observed differences are attributed to differences between the mass-loss history of the progenitor stars. We conclude that the progenitor of SN 2006jd likely experienced a significant mass-loss event during its pre-SN evolution akin to the great 19th century eruption of \eta Carinae. Contrarily, as advocated by Smith et al. (2009), we find the circumstellar environment of SN 2005ip to be more consistent with a clumpy wind progenitor.