Low Redshift Baryon Acoustic Oscillation Measurement from the
  Reconstructed 6-degree Field Galaxy Survey
  Low redshift measurements of Baryon Acoustic Oscillations (BAO) test the late
time evolution of the Universe and are a vital probe of Dark Energy. Over the
past decade both the 6-degree Field Galaxy Survey (6dFGS) and Sloan Digital Sky
Survey (SDSS) have provided important distance constraints at $z < 0.3$. In
this paper we re-evaluate the cosmological information from the BAO detection
in 6dFGS making use of HOD populated COLA mocks for a robust covariance matrix
and taking advantage of the now commonly implemented technique of density field
reconstruction. For the 6dFGS data, we find consistency with the previous
analysis, and obtain an isotropic volume averaged distance measurement of
$D_{V}(z_{\mathrm{eff}}=0.097) =
372\pm17(r_{s}/r_{s}^{\mathrm{fid}})\,\mathrm{Mpc}$, which has a non-Gaussian
likelihood outside the $1\sigma$ region. We combine our measurement from both
the post-reconstruction clustering of 6dFGS and SDSS MGS offering the most
robust constraint to date in this redshift regime,
$D_{V}(z_{\mathrm{eff}}=0.122)=539\pm17(r_{s}/r^{\mathrm{fid}}_{s})\,\mathrm{Mpc}$.
These measurements are consistent with standard $\Lambda\mathrm{CDM}$ and after
fixing the standard ruler using a Planck prior on $\Omega_{m}h^{2}$, the joint
analysis gives $H_{0}=64.0\pm3.5\,\mathrm{kms}^{-1}\mathrm{Mpc}^{-1}$. In the
near future both the Taipan Galaxy Survey and the Dark Energy Spectroscopic
Instrument (DESI) will improve this measurement to $1\%$ at low redshift.
