2016ApJ...822....6D

We present extensive optical (UBV RI, g^′^r′ⁱ′^z′^, and open CCD) and near-infrared (ZY JH) photometry for the very nearby Type IIP SN 2013ej extending from +1 to +461 days after shock breakout, estimated to be MJD 56496.9 ± 0.3. Substantial time series ultraviolet and optical spectroscopy obtained from +8 to +135 days are also presented. Considering well-observed SNe IIP from the literature, we derive UBV RIJHK bolometric calibrations from UBV RI and unfiltered measurements that potentially reach 2% precision with a B - V color-dependent correction. We observe moderately strong Si II λ6355 as early as +8 days. The photospheric velocity (v_ph) is determined by modeling the spectra in the vicinity of Fe II λ5169 whenever observed, and interpolating at photometric epochs based on a semianalytic method. This gives v_ph=4500±500 km s^–1 at +50 days. We also observe spectral homogeneity of ultraviolet spectra at +10-12 days for SNe IIP, while variations are evident a week after explosion. Using the expanding photosphere method, from combined analysis of SN 2013ej and SN 2002ap, we estimate the distance to the host galaxy to be 9.0_–0.6^+0.4 Mpc, consistent with distance estimates from other methods. Photometric and spectroscopic analysis during the plateau phase, which we estimated to be 94 ± 7 days long, yields an explosion energy of 0.9±0.3×10⁵¹ erg, a final pre-explosion progenitor mass of 15.2 ± 4.2 M_☉ and a radius of 250 ± 70 R_☉. We observe a broken exponential profile beyond +120 days, with a break point at +183 ± 16 days. Measurements beyond this break time yield a ⁵⁶Ni mass of 0.013 ± 0.001 M_☉.