Optical and Near-infrared Observations of SN 2013dx Associated with GRB 130702A

Abstract

We present optical and near-infrared (NIR) light curves and optical spectra of SN 2013dx, associated with the nearby (redshift 0.145) gamma-ray burst GRB 130702A. The prompt isotropic gamma- ray energy released from GRB 130702A is measured to be E${}_{\gamma },iso$=6.4${}_{-}1.0$${}^{+}1.3$× 10${}^{5}0$ erg (1 keV to 10 MeV in the rest frame), placing it intermediate between low-luminosity GRBs like GRB 980425/SN 1998bw and the broader cosmological population. We compare the observed g'r'I’ z’ light curves of SN 2013dx to a SN 1998bw template, finding that SN 2013dx evolves ̃20% faster (steeper rise time), with a comparable peak luminosity. Spectroscopically, SN 2013dx resembles other broad-lined SNe Ic, both associated with (SN 2006aj and SN 1998bw) and lacking (SN 1997ef, SN 2007I, and SN 2010ah) gamma-ray emission, with photospheric velocities around peak of ̃ 21,000 km s${}^{-}1$. We construct a quasi-bolometric (g'r'$^I'z'y) light curve for SN 2013dx, only the fifth GRB- associated SN with extensive NIR coverage and the third with a bolometric light curve extending beyond Δ t> 40 days. Together with the measured photospheric velocity, we derive basic explosion parameters using simple analytic models. We infer a ^{56$NimassofM$_Ni$=0.37+/-0.01M$_☉ $,anejectamassofM$_ej$=3.1+/-0.1M$_☉ $,andakineticenergyofE$_K$=(8.2+/-0.43)\times 10$^51$erg(statisticaluncertaintiesonly),consistentwithpreviousGRB-associatedsupernovae.WhenconsideringtheensemblepopulationofGRB-associatedsupernovae,wefindnocorrelationbetweenthemassofsynthesized$^56$Niandhigh-energyproperties,despiteclearpredictionsfromnumericalsimulationsthatM$_Ni$shouldcorrelatewiththedegreeofasymmetry.Ontheotherhand,M$_Ni$ clearly correlates with the kinetic energy of the supernova ejecta across a wide range of core-collapse events.}