Click here to flash read.
In recent years, there has been ample evidence that Type Ia supernova (SNe
Ia) with high Si II velocities near peak brightness are distinguished from SNe
Ia of lower velocities and may indeed represent a separate progenitor system.
These SNe Ia can contaminate the population of normal events used for
cosmological analyses, creating unwanted biases in the final analyses. Given
that many current and future surveys using SNe Ia as cosmological probes will
not have the resources to take a spectrum of all the events, likely only
getting host redshifts long after the SNe Ia have faded, we need to turn to
methods that could separate these populations based purely on photometry or
host properties. Here, we present a study of a sample of well observed, nearby
SNe Ia and their hosts to determine if there are significant enough differences
between these populations that can be discerned only from the stellar
population properties of their hosts. Our results indicate that the global host
properties, including star formation, stellar mass, stellar population age, and
dust attenuation, of high velocity SNe Ia do not differ significantly from
those of lower velocities. However, we do find that high velocity SNe Ia are
more concentrated toward the center of their hosts and have stronger Na I D
equivalent widths, suggesting that their local environments may indeed differ.
Future work requires strengthening photometric probes of high velocity SNe Ia
and their local environments to distinguish these events and determine if they
originate from a separate progenitor.
No creative common's license