We present ground-based and Swift photometric and spectroscopic observations of the candidate tidal disruption event ( TDE ) ASASSN-14li , found at the center of PGC 043234 ( d \simeq 90 Mpc ) by the All-Sky Automated Survey for SuperNovae ( ASAS-SN ) .
The source had a peak bolometric luminosity of L \simeq 10 ^ { 44 } ergs s ^ { -1 } and a total integrated energy of E \simeq 7 \times 10 ^ { 50 } ergs radiated over the \sim 6 months of observations presented .
The UV/optical emission of the source is well-fit by a blackbody with roughly constant temperature of T \sim 35 , 000 K , while the luminosity declines by roughly a factor of 16 over this time .
The optical/UV luminosity decline is broadly consistent with an exponential decline , L \propto e ^ { - t / t _ { 0 } } , with t _ { 0 } \simeq 60 days .
ASASSN-14li also exhibits soft X-ray emission comparable in luminosity to the optical and UV emission but declining at a slower rate , and the X-ray emission now dominates .
Spectra of the source show broad Balmer and helium lines in emission as well as strong blue continuum emission at all epochs .
We use the discoveries of ASASSN-14li and ASASSN-14ae to estimate the TDE rate implied by ASAS-SN , finding an average rate of r \simeq 4.1 \times 10 ^ { -5 } ~ { } { yr } ^ { -1 } per galaxy with a 90 % confidence interval of ( 2.2 - 17.0 ) \times 10 ^ { -5 } ~ { } { yr } ^ { -1 } per galaxy .
ASAS-SN found roughly 1 TDE for every 70 Type Ia supernovae in 2014 , a rate that is much higher than that of other surveys .