A sample of metal-poor galaxies identified from the LAMOST spectral
  survey
  We present a sample of 48 metal-poor galaxies at $ z < 0.14$ selected from
92,510 galaxies in the LAMOST survey. These galaxies are identified for their
detection of the auroral emission line \oiii$\lambda$4363 above $3\sigma$
level, which allows a direct measurement of the electron temperature and the
oxygen abundance. The emission line fluxes are corrected for internal dust
extinction using Balmer decrement method. With electron temperature derived
from \oiii$\lambda\lambda4959,5007/\oiii\lambda4363$ and electron density from
$\sii\lambda6731/\sii\lambda6717$, we obtain the oxygen abundances in our
sample which range from $\zoh= 7.63$ (0.09 $\Zsun$) to $8.46$ (0.6 $\Zsun$). We
find an extremely metal-poor galaxy with $\zoh=7.63 \pm 0.01$. With multiband
photometric data from FUV to NIR and $\ha$ measurements, we also determine the
stellar masses and star formation rates, based on the spectral energy
distribution fitting and $\ha$ luminosity, respectively. We find that our
galaxies have low and intermediate stellar masses with $\rm 6.39 \le
log(M/M_{\sun})\le 9.27$, and high star formation rates (SFRs) with $\rm -2.18
\le log(SFR/M_{\sun} yr^{-1}) \le 1.95$. We also find that the metallicities of
our galaxies are consistent with the local $T_e$-based mass-metallicity
relation, while the scatter is about 0.28 dex. Additionally, assuming the
coefficient of $\rm \alpha =0.66$, we find most of our galaxies follow the
local mass-metallicity-SFR relation, while a scatter about 0.24 dex exists,
suggesting the mass-metallicity relation is weakly dependent on SFR for those
metal-poor galaxies.
