Spectroscopic Identification and Chemical Distribution of HII Regions in
  the Galactic Anti-center Area from LAMOST
  We spectroscopically identify 101 Galactic HII regions using spectra from the
Large Sky Area Multi- Object Fiber Spectroscopic Telescope (LAMOST) survey,
cross-matched with an HII region catalog derived from the all-sky Wide-Field
Infrared Survey Explorer(WISE) data. Among all HII regions in our sample, 47
sources are newly confirmed. Spatially, most of our identified HII regions are
located in the anti-center area of the Galaxy. For each of the HII regions, we
accurately extract and measure the nebular emission lines of the spectra, and
estimate the oxygen abundances using the strong-line method. We focus on the
abundance distribution of HII regions in the Galactic anti-center area.
Accordingly, we derive the oxygen abundance gradient with a slope of -0.036
+/-0.004 dex/kpc, covering a range of RG from 8.1 to 19.3 kpc. In particular,
we also fit the outer disk objects with a slope of -0.039 +/- 0.012 dex /kpc,
which indicates that there is no flattening of the radial oxygen gradient in
the outer Galactic disk.
