On 2014 Dec. 9.61 , the All-Sky Automated Survey for SuperNovae ( ASAS-SN or ‘ ‘ Assassin ’ ’ ) discovered ASASSN-14lp just \sim 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 ( \Delta m _ { 15 } ( B ) = 0.80 \pm 0.05 ) , a B -band maximum at 2457015.82 \pm 0.03 , a rise time of 16.94 ^ { +0.11 } _ { -0.10 } days , and moderate host–galaxy extinction ( E ( B - V ) _ { \textrm { host } } = 0.33 \pm 0.06 ) .
Using ASASSN-14lp we derive a distance modulus for NGC 4666 of \mu = 30.8 \pm 0.2 corresponding to a distance of 14.7 \pm 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 non-degenerate companion larger than 0.34 R _ { \odot } .