We present a new method to photometrically delineate between various sub-types of Type Ia supernovae (SNe Ia). Using the color-stretch parameters, s BV or s gr , and the time of i -band primary maximum relative to the B -band ( ##IMG## [http://ej.iop.org/images/2041-8205/895/1/L3/apjlab8e37ieqn1.gif] {${t}_{\max }^{i-B}$} ) or g -band ( ##IMG## [http://ej.iop.org/images/2041-8205/895/1/L3/apjlab8e37ieqn2.gif] {${t}_{\max }^{i-g}$} ) maximum it is demonstrated that 2003fg-like, 1991bg-like, and 2002cx-like SNe Ia can be identified readily. In the cases of these extreme SNe Ia, their primary i -band maximum occurs after the time of the B- or g -band maxima. We suggest that the timing of the i -band maximum can reveal the physical state of the SN Ia explosion as it traces: (i) the speed of the recombination front of iron group elements in the eject...

中文翻译：

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卡内基超新星计划II：一种新的光度法识别Ia型超新星亚型的新方法

我们提出了一种新的方法，以光度法勾画出Ia型超新星（SNe Ia）的各种亚型之间的轮廓。使用颜色拉伸参数s BV或s gr，以及i波段相对于B波段的最大时间（## IMG ## [http://ej.iop.org/images/2041-8205 /895/1/L3/apjlab8e37ieqn1.gif] {$ {t} _ {\ max} ^ {iB} $}）或g波段（## IMG ## [http://ej.iop.org/images /2041-8205/895/1/L3/apjlab8e37ieqn2.gif] {$ {t} _ {\ max} ^ {ig} $}）最大值表明2003fg类，1991bg类和2002cx类SNe Ia可以很容易地识别出来。在这些极端SNe Ia的情况下，它们的主要i波段最大值出现在B波段或g波段最大值之后。我们建议，i波段最大值的时机可以揭示SN Ia爆炸的物理状态，因为它跟踪：（i）弹射中铁族元素重组前沿的速度...