TY - JOUR

T1 - The Exotic Type Ic Broad-lined Supernova SN 2018gep

T2 - Blurring the Line between Supernovae and Fast Optical Transients

AU - Pritchard, T. A.

AU - Bensch, Katarzyna

AU - Modjaz, Maryam

AU - Williamson, Marc

AU - Thone, Christina C.

AU - Vinko, J.

AU - Bianco, Federica B.

AU - Bostroem, K. Azalee

AU - Burke, Jamison

AU - Garcia-Benito, Ruben

AU - Galbany, L.

AU - Hiramatsu, Daichi

AU - Howell, D. Andrew

AU - Izzo, Luca

AU - Kann, D. Alexander

AU - McCully, Curtis

AU - Pellegrino, Craig

AU - de Ugarte Postigo, Antonio

AU - Valenti, Stefano

AU - Wang, Xiaofeng

AU - Wheeler, J. C.

AU - Xiang, Danfeng

AU - Sarneczky, K.

AU - Bodi, A.

AU - Cseh, B.

AU - Tarczay-Nehez, D.

AU - Kriskovics, L.

AU - Ordasi, A.

AU - Pal, A.

AU - Szakats, R.

AU - Vida, K.

PY - 2021/7/15

Y1 - 2021/7/15

N2 - In the last decade a number of rapidly evolving transients have been discovered that are not easily explained by traditional supernova models. We present optical and UV data on one such object, SN 2018gep, that displayed a fast rise with a mostly featureless blue continuum around peak, and evolved to develop broad features typical of an SN Ic-bl while retaining significant amounts of blue flux throughout its observations. This blue excess is most evident in its near-UV flux, which is over 4 mag brighter than other stripped-envelope supernovae, and is still visible in optical g-r colors. Its fast rise time of t (rise,V ) = 5.6 +/- 0.5 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 ( v ) = -19.53 +/- 0.23 mag it is on the extreme end of both the rise time and peak magnitude distribution for SNe Ic-bl. These 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. We show that SN 2018gep and the literature SN iPTF16asu have similar photometric and spectroscopic properties and that they overall share many similarities with both SNe Ic-bl and Fast Evolving Transients. Based on our SN 2018gep host galaxy data we derive a number of properties, and we show that the derived host galaxy properties for both SN 2018gep and iPTF16asu are consistent with the SNe Ic-bl and gamma-ray burst/supernova sample while being on the extreme edge of the observed Fast Evolving Transient sample.

AB - In the last decade a number of rapidly evolving transients have been discovered that are not easily explained by traditional supernova models. We present optical and UV data on one such object, SN 2018gep, that displayed a fast rise with a mostly featureless blue continuum around peak, and evolved to develop broad features typical of an SN Ic-bl while retaining significant amounts of blue flux throughout its observations. This blue excess is most evident in its near-UV flux, which is over 4 mag brighter than other stripped-envelope supernovae, and is still visible in optical g-r colors. Its fast rise time of t (rise,V ) = 5.6 +/- 0.5 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 ( v ) = -19.53 +/- 0.23 mag it is on the extreme end of both the rise time and peak magnitude distribution for SNe Ic-bl. These 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. We show that SN 2018gep and the literature SN iPTF16asu have similar photometric and spectroscopic properties and that they overall share many similarities with both SNe Ic-bl and Fast Evolving Transients. Based on our SN 2018gep host galaxy data we derive a number of properties, and we show that the derived host galaxy properties for both SN 2018gep and iPTF16asu are consistent with the SNe Ic-bl and gamma-ray burst/supernova sample while being on the extreme edge of the observed Fast Evolving Transient sample.

KW - INTEGRAL FIELD SPECTROSCOPY

KW - MASS-METALLICITY RELATION

KW - POTSDAM MULTIAPERTURE SPECTROPHOTOMETER

KW - RAPIDLY EVOLVING TRANSIENTS

KW - SUPERLUMINOUS SUPERNOVAE

KW - STRIPPED-ENVELOPE

KW - HOST GALAXIES

KW - LIGHT CURVES

KW - X-RAY

KW - SHOCK BREAKOUT

U2 - 10.3847/1538-4357/ac00bc

DO - 10.3847/1538-4357/ac00bc

M3 - Journal article

VL - 915

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 121

ER -