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We present progenitor mass constraints on supernovae (SNe), from correlations with star-forming regions within host galaxies. Through a pixel statistics method used together with H-alpha imaging of host galaxies, we present a progenitor mass sequence running from supernovae type Ia (SNIa) arising from the lowest, through SNII, SNIb, and finally SNIc arising from the highest mass progenitors, implied from an increasing association of their explosion sites with star formation (SF). We also present constraints on the various core-collapse (CC) sub-types, finding the perhaps surprising result that SNIIn show the lowest degree of association with SF of any CC type, implying relatively low-mass progenitors. Finally, we compare the SNIIn environment distribution to that of SNIa, posing the provocative question that additional SNIIn may be linked to the SNIa phenomenon where the latter's spectra are hidden beneath that of circumstellar material (CSM) interaction.

Dessart et al., demonstrated that type II supernova (SN II) model spectra present increasing metal line strength with increasing progenitor metallicity. To confront these models with observations, we obtained a large sample of SN II host H ii region emission line spectroscopy. We show that inferred SN II host H ii region metallicities have a statistically significant correlation with the strength of SN II metal lines, specifically Fe ii 5018Å.

We present optical photometry and spectrosopy of the transient SN 2011A. Our data spans 140 days after discovery including BVRIu'g'r'i'z' photometry and a sequence of 11 spectra. First classified as a type IIn supernova due to the presence of narrow Hα emission, this object shows exceptional characteristics. Firstly, the light curve shows a double plateau; a property only before observed in the impostor object SN 1997bs. Secondly SN 2011A has a very low luminosity for a type IIn supernova placing it between the type IIn supernovae and impostor classes in terms of luminosity. Thirdly, SN 2011A shows low velocity and high equivalent width sodium doublet absorption which increases with time and is most likely of circumstellar origin. This evolution is also accompanied by a change of line profile. When the absorption becomes stronger, a P-Cygni profile appears.

We present an analysis of V-band light-curves morphologies of type II supernovae (SNII). This investigation is achieved through photometry of more than 100 SNe including a first analysis of SNII data obtained by the Carnegie Supernova Project (CSP). We define the important observables and present correlations between SNe absolute magnitudes and light-curve decline rates: we find that brighter SNII tend to have faster declining light-curves at all epochs.