Distance and properties of NGC 4993 as the host galaxy of a
  gravitational wave source, GW170817
  Recently, the optical counterpart of a gravitational wave source GW170817 has
been identified in NGC 4993 galaxy. Together with evidence from observations in
electromagnetic waves, the event has been suggested as a result of a merger of
two neutron stars. We analyze the multi-wavelength data to characterize the
host galaxy property and its distance to examine if the properties of NGC 4993
are consistent with this picture. Our analysis shows that NGC 4993 is a
bulge-dominated galaxy with reff ~ 2-3 kpc and the Sersic index of n = 3-4 for
the bulge component. The spectral energy distribution from 0.15 to 24 micron
indicates that this galaxy has no significant ongoing star formation, the mean
stellar mass of (0.3 - 1.2) times 10^11 Msun,the mean stellar age greater than
~3 Gyr, and the metallicity of about 20% to 100% of solar abundance. Optical
images reveal dust lanes and extended features that suggest a past merging
activity. Overall, NGC 4993 has characteristics of normal, but slightly
disturbed elliptical galaxies. Furthermore, we derive the distance to NGC 4993
with the fundamental plane relation using 17 parameter sets of 7 different
filters and the central stellar velocity dispersion from literature, finding an
angular diameter distance of 37.7 +- 8.7 Mpc. NGC 4993 is similar to some host
galaxies of short gamma-ray bursts but much different from those of long
gamma-ray bursts, supporting the picture of GW170817 as a result of a merger of
two NSs.
