Optical and near-infrared observations of SN 2013dx associated with GRB 130702A

We present optical and near-infrared 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 $E_{gamma,iso}=6.4_{-1.0}^{+1.3}times10^{50}$erg (1keV-10MeV 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 $griz$ 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 Type Ic supernovae, 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 ~21,000km s$^{-1}$. We construct a quasi-bolometric ($grizyJ$) 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 $Delta t>40$d. Together with the measured photospheric velocity, we derive basic explosion parameters using simple analytic models. We infer a $^{56}$Ni mass of $M_{mathrm{Ni}}=0.37pm0.01$M$_{odot}$, an ejecta mass of $M_{mathrm{ej}}=3.1pm0.1$M$_{odot}$, and a kinetic energy of $E_{mathrm{K}}=(8.2pm0.43)times10^{51}$ erg (statistical uncertainties only), consistent with previous GRB-associated SNe. When considering the ensemble population of GRB-associated SNe, we find no correlation between the mass of synthesized $^{56}$Ni and high-energy properties, despite clear predictions from numerical simulations that $M_{mathrm{Ni}}$ should correlate with the degree of asymmetry. On the other hand, $M_{mathrm{Ni}}$ clearly correlates with the kinetic energy of the supernova ejecta across a wide range of core-collapse events.