Revisiting the Local Star-Forming Galaxies Observed in the HETDEX Pilot
  Survey
  I have reanalyzed the data obtained for local ($z<0.15$) star-forming
galaxies during the pilot survey for the Hobby-Eberly Telescope Dark Energy
Experiment (HETDEX)---called the HETDEX Pilot Survey (HPS)---which uses an
integral-field-unit spectrograph and covers $\sim3500-5800$ $\unicode{x212B}$
at $\sim5$ $\unicode{x212B}$ resolution. I have newly determined the gas
metallicities, $12 + \text{log(O/H)}$, following the Bayesian analysis scheme
of the previous study, but dealing carefully with the uncertainty of
strong-line calibration, performing reproducibility tests with mock data, and
monitoring the convergence of the Markov-Chain Monte Carlo (MCMC) sampling.
From the mock-data tests, I found that the nebular emission-line color excess
$E(B-V)$ can be overestimated by as much as 2-$\sigma$ or more, although the
metallicity can recover the input value to within 1-$\sigma$. The new
metallicity estimates on the HPS data are from well-converged MCMC samples
(effective sample sizes $>$ 2000), and they are higher than the previous
estimates by $\sim$2-$\sigma$. Using the HPS data, I also showed that the MCMC
sampling can have the statistical accuracy as poor as the one near the
iteration start if done without convergence monitoring. The overestimation of
$E(B-V)$ indicates the overestimation of the star-formation rates (SFRs) in the
previous study, which can be as much as a factor of five. This finding
undermines the previous suggestion of a hitherto-unknown galaxy population
based on the locations of galaxies in the mass-SFR plane. I found that the
independent determination of $E(B-V)$ using either H${\beta}$-H${\gamma}$ or
H${\alpha}$-H${\beta}$ line pair is ideal for the analysis of forthcoming
HETDEX data, but it requires additional cost.
