We report a multiwavelength (X-ray, ultraviolet/optical/infrared, radio) analysis of the relativistic tidal disruption event candidate Sw J2058+05 from 3 months to 3 yr post-discovery in order to study its properties and compare its behavior with tha
t of Sw J1644+57. Our main results are as follows. (1) The long-term X-ray light curve of Sw J2058+05 shows a remarkably similar trend to that of Sw J1644+57. After a prolonged power-law decay, the X-ray flux drops off rapidly by a factor of $gtrsim 160$ within a span of $Delta$$t$/$t$ $le$ 0.95. Associating this sudden decline with the transition from super-Eddington to sub-Eddington accretion, we estimate the black hole mass to be in the range of $10^{4-6}$ M$_{odot}$. (2) We detect rapid ($lesssim 500$ s) X-ray variability before the dropoff, suggesting that, even at late times, the X-rays originate from close to the black hole (ruling out a forward-shock origin). (3) We confirm using HST and VLBA astrometry that the location of the source coincides with the galaxys center to within $lesssim 400$ pc (in projection). (4) We modeled Sw J2058+05s ultraviolet/optical/infrared spectral energy distribution with a single-temperature blackbody and find that while the radius remains more or less constant at a value of $63.4 pm 4.5$ AU ($sim 10^{15}$ cm) at all times during the outburst, the blackbody temperature drops significantly from $sim$ 30,000 K at early times to a value of $sim$ 15,000 K at late times (before the X-ray dropoff). Our results strengthen Sw J2058+05s interpretation as a tidal disruption event similar to Sw J1644+57.
