7 research outputs found
The Exotic Type Ic Broad-Lined Supernova SN 2018gep: Blurring the Line Between Supernovae and Fast Optical Transients
In the last decade a number of rapidly evolving transients have been
discovered that are not easily explained by traditional supernovae models. We
present optical and UV data on onee such object, SN 2018gep, that displayed a
fast rise with a mostly featureless blue continuum around maximum light, and
evolved to develop broad features more typical of a SN Ic-bl while retaining
significant amounts of blue flux throughout its observations. The blue excess
is most evident in its near-UV flux that is over 4 magnitudes brighter than
other stripped envelope supernovae, but also visible in optical gr colors at
early times. Its fast rise time of days
puts it squarely in the emerging class of Fast Evolving Luminous Transients, or
Fast Blue Optical Transients. With a peak absolute magnitude of M mag it is on the extreme end of both the rise time and peak magnitude
distribution for SNe Ic-bl. Only one other SN Ic-bl has similar properties,
iPTF16asu, for which less of the important early time and UV data have been
obtained. We show that the objects SNe 2018gep and iPTF16asu have similar
photometric and spectroscopic properties and that they overall share many
similarities with both SNe Ic-bl and Fast Evolving Transients. We obtain IFU
observations of the SN 2018gep host galaxy and derive a number of properties
for it. We show that the derived host galaxy properties for both SN 2018gep and
iPTF16asu are overall consistent with the SNe Ic-bl and GRB/SNe sample while
being on the extreme edge of the observed Fast Evolving Transient sample. These
photometric observations are consistent with a simple SN Ic-bl model that has
an additional form of energy injection at early times that drives the observed
rapid, blue rise, and we speculate that this additional power source may
extrapolate to the broader Fast Evolving Transient sample