2016ApJ...826..144S

On 2014 December 9.61, the All-sky Automated Survey for SuperNovae (ASAS-SN or "Assassin") discovered ASASSN-14lp just ∼2 days after first light using a global array of 14 cm diameter telescopes. ASASSN-14lp went on to become a bright supernova (V=11.94 mag), second only to SN 2014J for the year. We present prediscovery photometry (with a detection less than a day after first light) and ultraviolet through near-infrared photometric and spectroscopic data covering the rise and fall of ASASSN-14lp for more than 100 days. We find that ASASSN-14lp had a broad light curve ( Δ{m}_{15}(B)=0.80±0.05 ), a B-band maximum at 2457015.82±0.03, a rise time of {16.94}_{-0.10}^{+0.11} days, and moderate host-galaxy extinction ( E{(B-V)}_host=0.33±0.06 ). Using ASASSN-14lp, we derive a distance modulus for NGC 4666 of µ=30.8±0.2 , corresponding to a distance of 14.7±1.5 Mpc. However, adding ASASSN-14lp to the calibrating sample of Type Ia supernovae still requires an independent distance to the host galaxy. Finally, using our early-time photometric and spectroscopic observations, we rule out red giant secondaries and, assuming a favorable viewing angle and explosion time, any nondegenerate companion larger than 0.34 {R}_☉ .