First Cosmological Results using Type Ia Supernovae from the Dark Energy
  Survey: Measurement of the Hubble Constant
  We present an improved measurement of the Hubble constant (H_0) using the
'inverse distance ladder' method, which adds the information from 207 Type Ia
supernovae (SNe Ia) from the Dark Energy Survey (DES) at redshift 0.018 < z <
0.85 to existing distance measurements of 122 low redshift (z < 0.07) SNe Ia
(Low-z) and measurements of Baryon Acoustic Oscillations (BAOs). Whereas
traditional measurements of H_0 with SNe Ia use a distance ladder of parallax
and Cepheid variable stars, the inverse distance ladder relies on absolute
distance measurements from the BAOs to calibrate the intrinsic magnitude of the
SNe Ia. We find H_0 = 67.8 +/- 1.3 km s-1 Mpc-1 (statistical and systematic
uncertainties, 68% confidence). Our measurement makes minimal assumptions about
the underlying cosmological model, and our analysis was blinded to reduce
confirmation bias. We examine possible systematic uncertainties and all are
below the statistical uncertainties. Our H_0 value is consistent with estimates
derived from the Cosmic Microwave Background assuming a LCDM universe (Planck
Collaboration et al. 2018).
