We present ultraviolet through near-infrared ( NIR ) broad-band photometry , and visual-wavelength and NIR spectroscopy of Type Iax supernova ( SN ) 2012Z .
The data set consists of both early and late-time observations , including the first late phase NIR spectrum obtained for a spectroscopically classified SN Iax .
A detailed comparison is made to the well-observed Type Iax SN 2005hk , revealing a striking resemblance between the two objects .
Simple model calculations of its bolometric light curve suggest SN 2012Z produced \sim 0.3 M _ { \sun } of ^ { 56 } Ni , ejected about a Chandrasekhar mass of material , and had an explosion energy of \sim 10 ^ { 51 } erg , making it one of the brightest ( M _ { B } = -18.3 mag ) and most energetic SN Iax yet observed .
Early and late phase visual-wavelength spectra of SN 2012Z are found to resemble similar epoch spectra of SN 2005hk , with the main difference being the former exhibiting broader absorption features , which we attribute to variations in the distribution of ^ { 56 } { \mathrm { Ni } } .
The late phase ( + 269d ) NIR spectrum of SN 2012Z is found to broadly resemble similar epoch spectra of normal SNe Ia ; however , like other SNe Iax , corresponding visual-wavelength spectra differ substantially compared to all supernova types .
Constraints from the distribution of intermediate mass elements , e.g .
silicon and magnesium , indicate that the outer ejecta did not experience significant mixing during or after burning , and the late phase NIR line profiles suggests most of the ^ { 56 } { \mathrm { Ni } } is produced during high density burning .
The various observational properties of SN 2012Z are found to be consistent with the theoretical expectations of a Chandrasekhar mass white dwarf progenitor that experiences a pulsational delayed detonation , which produced several tenths of a solar mass of ^ { 56 } { \mathrm { Ni } } during the deflagration burning phase and little ( or no ) ^ { 56 } { \mathrm { Ni } } during the detonation phase .
Within this scenario only a moderate amount of Rayleigh-Taylor mixing occurs both during the deflagration and fallback phase of the pulsation , and the layered structure of the intermediate mass elements is a product of the subsequent denotation phase .
The fact that the SNe Iax population does not follow a tight brightness-decline relation similar to SNe Ia can then be understood in the framework of variable amounts of mixing during pulsational rebound and variable amounts of ^ { 56 } { \mathrm { Ni } } production during the early subsonic phase of expansion .