Fabry-Perot Absorption Line Spectroscopy of the Galactic Bar. II.
  Stellar Metallicities
  We measure the Ca II 8542 line strength in 3360 stars along three
lines-of-sight in the Galactic bar: (l,b) ~ (+/-5.0,-3.5) and Baade's Window,
using Fabry-Perot (FP) absorption line spectroscopy. This is the first attempt
to show that reliable absorption line strengths can be measured using FP
spectroscopy. The Ca II 8542 line is a good indicator of metallicity and its
calibration to [Fe/H] is determined for globular cluster red giants in previous
investigations. We derive such a calibration for the bulge giants and use it to
infer metallicities for our full red clump sample (2488 stars) at all three
lines-of-sight. We present the stellar metallicity distributions along the
major axis of the bar. We find the mean [Fe/H] = -0.09 +/- 0.04 dex in Baade's
Window, and find the distribution in this field to agree well with previous
works. We find gradients in the mean metallicity and its dispersion w.r.t
Baade's WIndow of -0.45 and -0.20 dex respectively at l = +5.5, and of -0.10
dex and -0.20 dex at l = -5.0. We detect a signature of a possible tidal stream
at l = +5.5, in both our velocity and metallicity distributions. Its radial
velocity indicates that it is not associated with the Sagittarius stream. We
also measure the metallicity of a bulge globular cluster NGC 6522 in our
Baade's Window field to be -0.90 +/- 0.10 dex, in agreement with recent
measurements of Zoccali et al. (2008). This agreement demonstrates the
reliability of our metallicity measurements.
